Database Management Quiz: SQL and Normalization

1. 9. The scheduler establishes the order in which the operations within concurrent transactions are executed.

True

False

The scheduler is responsible for determining the order in which the operations within concurrent transactions are executed. This is important in ensuring that the transactions are executed in a consistent and correct manner, avoiding any conflicts or inconsistencies. By establishing a specific order for the operations, the scheduler can ensure that the transactions are executed in a way that maintains the integrity of the data and avoids any potential issues that may arise from concurrent execution.

Explanation

The scheduler is responsible for determining the order in which the operations within concurrent transactions are executed. This is important in ensuring that the transactions are executed in a consistent and correct manner, avoiding any conflicts or inconsistencies. By establishing a specific order for the operations, the scheduler can ensure that the transactions are executed in a way that maintains the integrity of the data and avoids any potential issues that may arise from concurrent execution.

2. 6. Distributed processing shares a database's logical processing among two or more physically independent sites that are connected through a network.

True

False

Distributed processing involves dividing the processing tasks of a database among multiple physically independent sites that are connected through a network. This allows for the sharing of the database's logical processing, enabling more efficient and scalable operations. Therefore, the given statement that distributed processing shares a database's logical processing among physically independent sites connected through a network is true.

Explanation

Distributed processing involves dividing the processing tasks of a database among multiple physically independent sites that are connected through a network. This allows for the sharing of the database's logical processing, enabling more efficient and scalable operations. Therefore, the given statement that distributed processing shares a database's logical processing among physically independent sites connected through a network is true.

3. 8. The most useful feature of PL/SQL blocks is that they let a designer create code that can be named, stored, and executed by the DBMS.

True

False

PL/SQL blocks are a fundamental component of PL/SQL programming language. They allow designers to create reusable code that can be named, stored, and executed by the DBMS (Database Management System). This feature enhances code organization and reusability, making it easier to maintain and manage large codebases. Therefore, the statement is true.

Explanation

PL/SQL blocks are a fundamental component of PL/SQL programming language. They allow designers to create reusable code that can be named, stored, and executed by the DBMS (Database Management System). This feature enhances code organization and reusability, making it easier to maintain and manage large codebases. Therefore, the statement is true.

4. Although SQL commands can be grouped together on a single line, complex command sequences are best shown on separate lines, with space between the SQL command and the command's components.

True

False

Complex command sequences are best shown on separate lines with space between the SQL command and its components because it improves readability and makes it easier to understand the structure of the command sequence. By separating the commands onto separate lines, it becomes clearer where one command ends and the next one begins. Additionally, adding space between the SQL command and its components helps to visually distinguish the different parts of the command, making it easier to identify and interpret each component. This practice is especially important for complex command sequences that involve multiple SQL commands and components.

Explanation

Complex command sequences are best shown on separate lines with space between the SQL command and its components because it improves readability and makes it easier to understand the structure of the command sequence. By separating the commands onto separate lines, it becomes clearer where one command ends and the next one begins. Additionally, adding space between the SQL command and its components helps to visually distinguish the different parts of the command, making it easier to identify and interpret each component. This practice is especially important for complex command sequences that involve multiple SQL commands and components.

5. 22. The SQL command that allows a user to permanently save data changes is _____.

INSERT

SELECT

COMMIT

UPDATE

The SQL command "COMMIT" allows a user to permanently save data changes. When this command is executed, it confirms that all the changes made to the database should be saved permanently. It is used in conjunction with the "UPDATE" or "INSERT" commands to ensure that the changes made to the data are committed and not temporary. The "SELECT" command is used to retrieve data from the database and does not save any changes.

Explanation

The SQL command "COMMIT" allows a user to permanently save data changes. When this command is executed, it confirms that all the changes made to the database should be saved permanently. It is used in conjunction with the "UPDATE" or "INSERT" commands to ensure that the changes made to the data are committed and not temporary. The "SELECT" command is used to retrieve data from the database and does not save any changes.

6. 3. The ANSI SQL standards are also accepted by the ISO.

True

False

The explanation for the given answer is that the ANSI SQL standards, which stands for American National Standards Institute Structured Query Language standards, are indeed accepted by the ISO, which stands for International Organization for Standardization. This means that the SQL standards developed by ANSI are recognized and adopted internationally, ensuring interoperability and consistency in the use of SQL across different database management systems.

Explanation

The explanation for the given answer is that the ANSI SQL standards, which stands for American National Standards Institute Structured Query Language standards, are indeed accepted by the ISO, which stands for International Organization for Standardization. This means that the SQL standards developed by ANSI are recognized and adopted internationally, ensuring interoperability and consistency in the use of SQL across different database management systems.

7. 33. SQL requires the use of the _____ command to enter data into a table.

INSERT

SELECT

COMMIT

NOT NULL

SQL requires the use of the INSERT command to enter data into a table. The INSERT command allows users to add new rows of data into a specific table in the database. This command is essential for populating tables with the desired information and is a fundamental operation in SQL.

Explanation

SQL requires the use of the INSERT command to enter data into a table. The INSERT command allows users to add new rows of data into a specific table in the database. This command is essential for populating tables with the desired information and is a fundamental operation in SQL.

8. A database language enables the user to perform complex queries designed to transform the raw data into useful information.

True

False

A database language allows users to execute complex queries that can manipulate and transform raw data into meaningful information. This enables users to retrieve specific data, perform calculations, combine data from multiple tables, and generate reports or analysis. By using a database language, users can efficiently extract the desired information from a database, making it a valuable tool for data analysis and decision-making.

Explanation

A database language allows users to execute complex queries that can manipulate and transform raw data into meaningful information. This enables users to retrieve specific data, perform calculations, combine data from multiple tables, and generate reports or analysis. By using a database language, users can efficiently extract the desired information from a database, making it a valuable tool for data analysis and decision-making.

9. 2. Although the DBMS is designed to recover a database to a previous consistent state when an interruption prevents the completion of a required set of transactions, the transactions themselves are defined by the end user or programmer and must be semantically correct.

True

False

The statement is true because while a DBMS is designed to recover a database to a previous consistent state in the event of an interruption, the responsibility of defining the transactions and ensuring their semantic correctness lies with the end user or programmer. The DBMS can only ensure the consistency and integrity of the database based on the transactions it is provided with, but it does not have control over the correctness of the transactions themselves.

Explanation

The statement is true because while a DBMS is designed to recover a database to a previous consistent state in the event of an interruption, the responsibility of defining the transactions and ensuring their semantic correctness lies with the end user or programmer. The DBMS can only ensure the consistency and integrity of the database based on the transactions it is provided with, but it does not have control over the correctness of the transactions themselves.

10. 1. A view is a virtual table based on a SELECT query.

True

False

Option 3

Option 4

A view is a virtual table that is created based on the result of a SELECT query. It does not store any data itself but instead provides a way to access and manipulate data from one or more tables. By using views, users can simplify complex queries, restrict access to certain columns or rows, and present data in a more meaningful way. Therefore, the statement that "a view is a virtual table based on a SELECT query" is true.

Explanation

A view is a virtual table that is created based on the result of a SELECT query. It does not store any data itself but instead provides a way to access and manipulate data from one or more tables. By using views, users can simplify complex queries, restrict access to certain columns or rows, and present data in a more meaningful way. Therefore, the statement that "a view is a virtual table based on a SELECT query" is true.

11. 10. A scheduler facilitates data isolation to ensure that two transactions do not update the same data element at the same time.

True

False

A scheduler is responsible for managing the execution of transactions in a database system. One of its key functions is to ensure data isolation, which means that multiple transactions can access and modify data concurrently without interfering with each other. By preventing two transactions from updating the same data element at the same time, the scheduler ensures that the integrity of the data is maintained and conflicts are avoided. Therefore, the statement that a scheduler facilitates data isolation to prevent simultaneous updates is true.

Explanation

A scheduler is responsible for managing the execution of transactions in a database system. One of its key functions is to ensure data isolation, which means that multiple transactions can access and modify data concurrently without interfering with each other. By preventing two transactions from updating the same data element at the same time, the scheduler ensures that the integrity of the data is maintained and conflicts are avoided. Therefore, the statement that a scheduler facilitates data isolation to prevent simultaneous updates is true.

12. 10. In order to manage distributed data, copies or parts of the database processing functions must be distributed to all data storage sites.

True

False

In order to manage distributed data effectively, it is necessary to distribute copies or parts of the database processing functions to all data storage sites. This ensures that each site can process and manage its own data efficiently, without relying on a central processing unit. By distributing the processing functions, the workload is distributed across multiple sites, allowing for better performance and scalability in managing distributed data. Therefore, the statement "In order to manage distributed data, copies or parts of the database processing functions must be distributed to all data storage sites" is true.

Explanation

In order to manage distributed data effectively, it is necessary to distribute copies or parts of the database processing functions to all data storage sites. This ensures that each site can process and manage its own data efficiently, without relying on a central processing unit. By distributing the processing functions, the workload is distributed across multiple sites, allowing for better performance and scalability in managing distributed data. Therefore, the statement "In order to manage distributed data, copies or parts of the database processing functions must be distributed to all data storage sites" is true.

13. 11. String comparisons are made from left to right.

True

False

String comparisons are made from left to right means that when comparing two strings, the comparison starts from the leftmost character and continues until a difference is found or the end of the strings is reached. This means that the characters in the strings are compared one by one in the order they appear. If a difference is found, the comparison stops and the result is determined based on the ASCII values of the differing characters. Therefore, the given statement "True" is correct.

Explanation

String comparisons are made from left to right means that when comparing two strings, the comparison starts from the leftmost character and continues until a difference is found or the end of the strings is reached. This means that the characters in the strings are compared one by one in the order they appear. If a difference is found, the comparison stops and the result is determined based on the ASCII values of the differing characters. Therefore, the given statement "True" is correct.

14. 7. In Oracle, you can use the SQL*Plus command SHOW ERRORS to help you diagnose errors found in PL/SQL blocks.

True

False

The SQL*Plus command SHOW ERRORS in Oracle is used to display the compilation errors that occur in PL/SQL blocks. This command is helpful in identifying and diagnosing errors in the code, allowing developers to quickly locate and fix any issues. Therefore, the given statement is true.

Explanation

The SQL*Plus command SHOW ERRORS in Oracle is used to display the compilation errors that occur in PL/SQL blocks. This command is helpful in identifying and diagnosing errors in the code, allowing developers to quickly locate and fix any issues. Therefore, the given statement is true.

15. 23. The _____ command defines a default value for a column when no value is given.

CHECK

UNIQUE

NOT NULL

DEFAULT

The DEFAULT command is used to define a default value for a column when no value is given. This means that if a value is not specified for the column during an insert operation, the default value will be used instead.

Explanation

The DEFAULT command is used to define a default value for a column when no value is given. This means that if a value is not specified for the column during an insert operation, the default value will be used instead.

16. 3. To remedy the lack of procedural functionality in SQL, and to provide some standardization within the many vendor offerings, the SQL-99 standard defined the use of persistent stored modules.

True

False

Option 3

Option 4

The SQL-99 standard introduced the concept of persistent stored modules to address the lack of procedural functionality in SQL and to bring some standardization across different vendor offerings. These modules allow developers to write and store procedural code directly in the database, making it easier to implement complex logic and improve performance. Therefore, the statement "True" is the correct answer.

Explanation

The SQL-99 standard introduced the concept of persistent stored modules to address the lack of procedural functionality in SQL and to bring some standardization across different vendor offerings. These modules allow developers to write and store procedural code directly in the database, making it easier to implement complex logic and improve performance. Therefore, the statement "True" is the correct answer.

17. 13. SQL allows the use of logical restrictions on its inquiries such as OR, AND, and NOT.

True

False

SQL allows the use of logical restrictions such as OR, AND, and NOT in its inquiries. These logical operators allow users to combine conditions and create complex queries to retrieve specific data from a database. The OR operator allows the retrieval of data that satisfies at least one of the conditions, the AND operator retrieves data that satisfies all the conditions, and the NOT operator retrieves data that does not satisfy a particular condition. Therefore, the statement "SQL allows the use of logical restrictions on its inquiries such as OR, AND, and NOT" is true.

Explanation

SQL allows the use of logical restrictions such as OR, AND, and NOT in its inquiries. These logical operators allow users to combine conditions and create complex queries to retrieve specific data from a database. The OR operator allows the retrieval of data that satisfies at least one of the conditions, the AND operator retrieves data that satisfies all the conditions, and the NOT operator retrieves data that does not satisfy a particular condition. Therefore, the statement "SQL allows the use of logical restrictions on its inquiries such as OR, AND, and NOT" is true.

18. 19. The COUNT function is designed to tally the number of non-null "values" of an attribute, and is often used in conjunction with the DISTINCT clause.

True

False

Option 3

Option 4

The explanation for the given correct answer is that the COUNT function is indeed designed to count the number of non-null "values" of an attribute. It is commonly used in conjunction with the DISTINCT clause to count the unique non-null values in a column. Therefore, the statement is true.

Explanation

The explanation for the given correct answer is that the COUNT function is indeed designed to count the number of non-null "values" of an attribute. It is commonly used in conjunction with the DISTINCT clause to count the unique non-null values in a column. Therefore, the statement is true.

19. 36. Which comparison operator indicates a value is not equal?

<

<=

>=

<>

The comparison operator "<>" is used to indicate that a value is not equal to another value. This operator is commonly used in programming languages and databases to compare two values and return true if they are not equal.

Explanation

The comparison operator "<>" is used to indicate that a value is not equal to another value. This operator is commonly used in programming languages and databases to compare two values and return true if they are not equal.

20. 12. In a page-level lock, the DBMS will lock an entire diskpage.

True

False

In a page-level lock, the DBMS will lock an entire disk page. This means that when a lock is acquired on a specific page, the entire page is locked, preventing any other transactions from accessing or modifying any data within that page. This type of lock provides a higher level of concurrency control and ensures that the integrity of the data on the page is maintained.

Explanation

In a page-level lock, the DBMS will lock an entire disk page. This means that when a lock is acquired on a specific page, the entire page is locked, preventing any other transactions from accessing or modifying any data within that page. This type of lock provides a higher level of concurrency control and ensures that the integrity of the data on the page is maintained.

21. 25. A(n) _____ query specifies which data should be retrieved and how it should be filtered, aggregated, and displayed.

INSERT

SELECT

COMMIT

UPDATE

A SELECT query is used to specify which data should be retrieved from a database. It also allows for filtering, aggregating, and displaying the data based on specific criteria. This query is commonly used in SQL to retrieve information from tables and present it in a desired format.

Explanation

A SELECT query is used to specify which data should be retrieved from a database. It also allows for filtering, aggregating, and displaying the data based on specific criteria. This query is commonly used in SQL to retrieve information from tables and present it in a desired format.

22. 40. The SQL aggregate function that gives the number of rows containing non-null values for a given column is _____.

COUNT

MIN

MAX

SUM

The SQL aggregate function "COUNT" is used to count the number of rows that contain non-null values for a given column. It returns the total number of rows that meet the specified criteria. This function is commonly used to calculate the number of records in a table or the number of occurrences of a specific value in a column.

Explanation

The SQL aggregate function "COUNT" is used to count the number of rows that contain non-null values for a given column. It returns the total number of rows that meet the specified criteria. This function is commonly used to calculate the number of records in a table or the number of occurrences of a specific value in a column.

23. 35. Which command would be used to delete the table row where the P_CODE is 'BRT-345'?

DELETE FROM PRODUCTWHERE P_CODE = 'BRT-345';

REMOVE FROM PRODUCTWHERE P_CODE = 'BRT-345';

ERASE FROM PRODUCTWHERE P_CODE = 'BRT-345';

ROLLBACK FROM PRODUCTWHERE P_CODE = 'BRT-345';

The correct answer is "DELETE FROM PRODUCT WHERE P_CODE = 'BRT-345';" because the DELETE command is used to delete rows from a table, and the WHERE clause specifies the condition that must be met for the row to be deleted. In this case, the condition is that the P_CODE column must have a value of 'BRT-345'.

Explanation

The correct answer is "DELETE FROM PRODUCT WHERE P_CODE = 'BRT-345';" because the DELETE command is used to delete rows from a table, and the WHERE clause specifies the condition that must be met for the row to be deleted. In this case, the condition is that the P_CODE column must have a value of 'BRT-345'.

24. 2. A sequence is not associated with a table and can be dropped from a database with a DROP SEQUENCE command.

True

False

A sequence in a database is a user-defined object that generates a sequence of unique numbers. It is not associated with any specific table and can be used by multiple tables. Therefore, it can be dropped from the database using the DROP SEQUENCE command without affecting any data in the tables. Hence, the given statement is true.

Explanation

A sequence in a database is a user-defined object that generates a sequence of unique numbers. It is not associated with any specific table and can be used by multiple tables. Therefore, it can be dropped from the database using the DROP SEQUENCE command without affecting any data in the tables. Hence, the given statement is true.

25. 11. A trigger is procedural SQL code that is automatically invoked by the RDBMS upon the occurrence of a given data manipulation event.

True

False

A trigger is a type of procedural SQL code that is designed to automatically execute in response to a specific event occurring within a relational database management system (RDBMS). These events are typically data manipulation events, such as inserting, updating, or deleting data in a table. When the specified event occurs, the trigger is automatically invoked by the RDBMS, allowing it to perform a predefined set of actions or operations. Therefore, the statement "A trigger is procedural SQL code that is automatically invoked by the RDBMS upon the occurrence of a given data manipulation event" is true.

Explanation

A trigger is a type of procedural SQL code that is designed to automatically execute in response to a specific event occurring within a relational database management system (RDBMS). These events are typically data manipulation events, such as inserting, updating, or deleting data in a table. When the specified event occurs, the trigger is automatically invoked by the RDBMS, allowing it to perform a predefined set of actions or operations. Therefore, the statement "A trigger is procedural SQL code that is automatically invoked by the RDBMS upon the occurrence of a given data manipulation event" is true.

26. 26. A(n) _____ is an alternate name given to a column or table in any SQL statement.

Alias

Data type

Stored function

Trigger

In SQL, an alias is an alternate name given to a column or table in any SQL statement. It is used to provide a temporary name to a column or table, which can be helpful in making the SQL statement more readable and concise. Aliases can also be used to rename the output of a query or to provide a shorter name for a table or column with a long name.

Explanation

In SQL, an alias is an alternate name given to a column or table in any SQL statement. It is used to provide a temporary name to a column or table, which can be helpful in making the SQL statement more readable and concise. Aliases can also be used to rename the output of a query or to provide a shorter name for a table or column with a long name.

27. 13. A field-level lock allows concurrent transactions to access the same row, as long as they require the use of different fields within that row.

True

False

A field-level lock is a type of lock that allows multiple transactions to access the same row in a database concurrently, as long as they are accessing different fields within that row. This means that multiple transactions can read or write to different fields of the same row at the same time without conflicting with each other. This promotes concurrency and can improve the performance of the system by allowing multiple transactions to work on different fields of the same row simultaneously. Therefore, the given statement that a field-level lock allows concurrent transactions to access the same row as long as they require the use of different fields within that row is true.

Explanation

A field-level lock is a type of lock that allows multiple transactions to access the same row in a database concurrently, as long as they are accessing different fields within that row. This means that multiple transactions can read or write to different fields of the same row at the same time without conflicting with each other. This promotes concurrency and can improve the performance of the system by allowing multiple transactions to work on different fields of the same row simultaneously. Therefore, the given statement that a field-level lock allows concurrent transactions to access the same row as long as they require the use of different fields within that row is true.

28. 40. A _____ lock allows concurrent transactions to access different rows of the same table.

Database table

Page-level

Row-level

A row-level lock allows concurrent transactions to access different rows of the same table. This means that multiple transactions can read or write to different rows of the table simultaneously without blocking each other. This type of lock provides better concurrency and performance compared to page-level or table-level locks, as it allows for more granular control and reduces the chances of conflicts or contention between transactions.

Explanation

A row-level lock allows concurrent transactions to access different rows of the same table. This means that multiple transactions can read or write to different rows of the table simultaneously without blocking each other. This type of lock provides better concurrency and performance compared to page-level or table-level locks, as it allows for more granular control and reduces the chances of conflicts or contention between transactions.

29. 21. Transaction is a _____ unit of work that must be either entirely completed or aborted.

Time

Practical

Logical

Physical

A transaction is a logical unit of work because it represents a set of operations that are logically related and should be treated as a single, indivisible unit. This means that either all the operations in the transaction must be successfully completed, or if any operation fails, the entire transaction must be aborted and rolled back to its previous state. Therefore, the correct answer is "logical".

Explanation

A transaction is a logical unit of work because it represents a set of operations that are logically related and should be treated as a single, indivisible unit. This means that either all the operations in the transaction must be successfully completed, or if any operation fails, the entire transaction must be aborted and rolled back to its previous state. Therefore, the correct answer is "logical".

30. 32. A table can be deleted from the database by using the _____ TABLE command.

DROP

DELETE

MODIFY

ERASE

The correct answer is DROP. The DROP TABLE command is used to delete a table from the database. This command removes the entire table structure and all its data from the database. It is a commonly used command when a table is no longer needed or needs to be recreated with different structure or data.

Explanation

The correct answer is DROP. The DROP TABLE command is used to delete a table from the database. This command removes the entire table structure and all its data from the database. It is a commonly used command when a table is no longer needed or needs to be recreated with different structure or data.

31. 28. The _____ constraint is used to validate data when an attribute value is entered.

UNIQUE

CASCADE

CHECK

SET NULL

The CHECK constraint is used to validate data when an attribute value is entered. This constraint allows the user to define a condition that must be satisfied for the attribute value to be considered valid. When an attribute value is entered, it is checked against the specified condition, and if it does not meet the condition, the data entry is rejected.

Explanation

The CHECK constraint is used to validate data when an attribute value is entered. This constraint allows the user to define a condition that must be satisfied for the attribute value to be considered valid. When an attribute value is entered, it is checked against the specified condition, and if it does not meet the condition, the data entry is rejected.

32. 36. When a user issues the DELETE FROM tablename command without specifying a WHERE condition, _____.

No rows will be deleted

The first row will be deleted

The last row will be deleted

All rows will be deleted

When a user issues the DELETE FROM tablename command without specifying a WHERE condition, all rows in the table will be deleted. This is because the absence of a WHERE condition means that there are no constraints on which rows should be deleted, so the command will delete all rows in the table.

Explanation

When a user issues the DELETE FROM tablename command without specifying a WHERE condition, all rows in the table will be deleted. This is because the absence of a WHERE condition means that there are no constraints on which rows should be deleted, so the command will delete all rows in the table.

33. 42. In Oracle, _____ retrieves the current value of a sequence.

NEXTVAL

CURRVAL

VARCHAR

VARCHAR2

In Oracle, CURRVAL is used to retrieve the current value of a sequence. It is commonly used after the NEXTVAL function, which generates the next value in the sequence. CURRVAL allows you to obtain the current value without incrementing the sequence.

Explanation

In Oracle, CURRVAL is used to retrieve the current value of a sequence. It is commonly used after the NEXTVAL function, which generates the next value in the sequence. CURRVAL allows you to obtain the current value without incrementing the sequence.

34. 41. A(n) _____ is a query that is embedded (or nested) inside another query.

Alias

Operator

Subquery

View

A subquery is a query that is embedded or nested inside another query. It is used to retrieve data from one or more tables and is typically placed within the WHERE or HAVING clause of the outer query. The result of the subquery is then used by the outer query to perform further operations or filtering. Subqueries are useful for performing complex queries and can help in simplifying the overall query structure.

Explanation

A subquery is a query that is embedded or nested inside another query. It is used to retrieve data from one or more tables and is typically placed within the WHERE or HAVING clause of the outer query. The result of the subquery is then used by the outer query to perform further operations or filtering. Subqueries are useful for performing complex queries and can help in simplifying the overall query structure.

35. 37. The _____ command is used to restore the database to its previous condition.

ROWCOUNT

BACKUP

COMMIT

ROLLBACK

The ROLLBACK command is used to restore the database to its previous condition. This command is typically used in situations where a transaction needs to be undone or rolled back due to an error or failure. It allows the database to revert back to the state it was in before the transaction started, ensuring data consistency and integrity.

Explanation

The ROLLBACK command is used to restore the database to its previous condition. This command is typically used in situations where a transaction needs to be undone or rolled back due to an error or failure. It allows the database to revert back to the state it was in before the transaction started, ensuring data consistency and integrity.

36. 38. The special operator used to check whether an attribute value is within a range of values is _____.

BETWEEN

IS NULL

LIKE

IN

The special operator used to check whether an attribute value is within a range of values is "BETWEEN". This operator is used in SQL queries to specify a range of values for a particular attribute. It allows for inclusive range comparisons, where the attribute value must be between two specified values.

Explanation

The special operator used to check whether an attribute value is within a range of values is "BETWEEN". This operator is used in SQL queries to specify a range of values for a particular attribute. It allows for inclusive range comparisons, where the attribute value must be between two specified values.

37. 21. When you create a new database, the RDBMS automatically creates the data _____ tables in which to store the metadata and creates a default database administrator.

Index

Chapter

Dictionary

Appendix

When you create a new database, the RDBMS automatically creates the data dictionary tables in which to store the metadata and creates a default database administrator. The data dictionary is a collection of database objects that contains information about the structure, definitions, and relationships of the database. It stores information such as table names, column names, data types, constraints, and indexes. The RDBMS automatically creates these tables to manage and maintain the metadata of the database. The default database administrator is also created to have the necessary privileges and permissions to manage the database.

Explanation

When you create a new database, the RDBMS automatically creates the data dictionary tables in which to store the metadata and creates a default database administrator. The data dictionary is a collection of database objects that contains information about the structure, definitions, and relationships of the database. It stores information such as table names, column names, data types, constraints, and indexes. The RDBMS automatically creates these tables to manage and maintain the metadata of the database. The default database administrator is also created to have the necessary privileges and permissions to manage the database.

38. 24. The _____ specification creates an individual index on a respective attribute; use it to avoid having duplicated values in a column.

UNIQUE

NOT NULL

UPDATE

VARCHAR

The UNIQUE specification creates an individual index on a respective attribute. This means that each value in the column must be unique and cannot be duplicated. By using the UNIQUE specification, it helps to ensure data integrity and avoids having duplicate values in the column.

Explanation

The UNIQUE specification creates an individual index on a respective attribute. This means that each value in the column must be unique and cannot be duplicated. By using the UNIQUE specification, it helps to ensure data integrity and avoids having duplicate values in the column.

39. 30. Using the _____ command, SQL indexes can be created on the basis of any selected attribute.

CREATE INDEX

UPDATE CASCADE

SELECT

VARCHAR

The CREATE INDEX command in SQL allows for the creation of indexes on selected attributes. Indexes are used to improve the performance of database queries by providing a quick access path to the data. By creating an index on a specific attribute, the database can efficiently locate and retrieve the desired information. This command is essential for optimizing query performance in SQL databases.

Explanation

The CREATE INDEX command in SQL allows for the creation of indexes on selected attributes. Indexes are used to improve the performance of database queries by providing a quick access path to the data. By creating an index on a specific attribute, the database can efficiently locate and retrieve the desired information. This command is essential for optimizing query performance in SQL databases.

40. 34. The _____ command permanently saves all changes—such as rows added, attributes modified, and rows deleted—made to any table in the database.

COMMIT

SELECT

ROLLBACK

UPDATE

The COMMIT command is used in databases to permanently save all changes made to a table. It is typically used after executing a series of SQL statements to ensure that the changes are permanently saved and not rolled back. This command is important for maintaining data integrity and consistency in a database.

Explanation

The COMMIT command is used in databases to permanently save all changes made to a table. It is typically used after executing a series of SQL statements to ensure that the changes are permanently saved and not rolled back. This command is important for maintaining data integrity and consistency in a database.

41. SQL is considered difficult to learn; its command set has a vocabulary of more than 300 words

True

False

The statement that SQL is considered difficult to learn because its command set has a vocabulary of more than 300 words is false. While SQL does have a wide range of commands and keywords, the difficulty of learning SQL is subjective and can vary from person to person. Some individuals may find SQL easy to learn, while others may struggle with it. The number of words in its command set does not necessarily determine its difficulty level.

Explanation

The statement that SQL is considered difficult to learn because its command set has a vocabulary of more than 300 words is false. While SQL does have a wide range of commands and keywords, the difficulty of learning SQL is subjective and can vary from person to person. Some individuals may find SQL easy to learn, while others may struggle with it. The number of words in its command set does not necessarily determine its difficulty level.

42. 12. Triggers can only be used to update table values.

True

False

Triggers can be used to perform various actions, including updating table values, but they are not limited to just updating table values. Triggers can also be used to insert, delete, or perform other actions based on certain conditions or events occurring in the database. Therefore, the statement "Triggers can only be used to update table values" is false.

Explanation

Triggers can be used to perform various actions, including updating table values, but they are not limited to just updating table values. Triggers can also be used to insert, delete, or perform other actions based on certain conditions or events occurring in the database. Therefore, the statement "Triggers can only be used to update table values" is false.

43. 45. A(n) _____ condition occurs when two or more transactions wait for each other to unlock data.

Deadlock

Exclusive lock

Binary lock

Two-phase lock

A deadlock condition occurs when two or more transactions are waiting for each other to unlock data. In this state, none of the transactions can proceed, leading to a halt in the system. Deadlocks can happen when transactions acquire locks on resources and then request additional locks that are held by other transactions. Without proper management and prevention mechanisms, deadlocks can significantly impact the performance and functionality of a system.

Explanation

A deadlock condition occurs when two or more transactions are waiting for each other to unlock data. In this state, none of the transactions can proceed, leading to a halt in the system. Deadlocks can happen when transactions acquire locks on resources and then request additional locks that are held by other transactions. Without proper management and prevention mechanisms, deadlocks can significantly impact the performance and functionality of a system.

44. 13. The transaction processor (TP) is the software component found in each computer that requests data.

True

False

The statement is true because the transaction processor (TP) is indeed the software component found in each computer that requests data. The TP is responsible for handling and processing transactions, which involve retrieving and updating data from a database. It acts as an intermediary between the application and the database, ensuring that the requested data is retrieved accurately and securely. Therefore, it is correct to say that the TP is the software component responsible for requesting data.

Explanation

The statement is true because the transaction processor (TP) is indeed the software component found in each computer that requests data. The TP is responsible for handling and processing transactions, which involve retrieving and updating data from a database. It acts as an intermediary between the application and the database, ensuring that the requested data is retrieved accurately and securely. Therefore, it is correct to say that the TP is the software component responsible for requesting data.

45. Comparison operators cannot be used to place restrictions on character-based attributes.

True

False

The statement is false because comparison operators can indeed be used to place restrictions on character-based attributes. Comparison operators such as "==" or "!=" can be used to compare character-based attributes and determine if they meet certain conditions or restrictions. Therefore, the correct answer is False.

Explanation

The statement is false because comparison operators can indeed be used to place restrictions on character-based attributes. Comparison operators such as "==" or "!=" can be used to compare character-based attributes and determine if they meet certain conditions or restrictions. Therefore, the correct answer is False.

46. 24. The _____ command restricts the selection of grouped rows based on a condition.

DISPLAY

HAVING

FROM

CONVERT

The HAVING command is used to restrict the selection of grouped rows based on a condition. It is typically used in conjunction with the GROUP BY clause to filter the results of a query based on aggregate functions such as COUNT, SUM, AVG, etc. The HAVING command allows you to specify conditions that must be met by the groups in order to be included in the result set.

Explanation

The HAVING command is used to restrict the selection of grouped rows based on a condition. It is typically used in conjunction with the GROUP BY clause to filter the results of a query based on aggregate functions such as COUNT, SUM, AVG, etc. The HAVING command allows you to specify conditions that must be met by the groups in order to be included in the result set.

47. The COMMIT command does not permanently save all changes. In order to do that, you must use SAVE.

True

False

The statement is incorrect. The COMMIT command is used to permanently save all changes made in a transaction. It is not necessary to use the SAVE command for this purpose.

Explanation

The statement is incorrect. The COMMIT command is used to permanently save all changes made in a transaction. It is not necessary to use the SAVE command for this purpose.

48. 1. Most real-world database transactions are formed by only one database request.

True

False

Most real-world database transactions are not formed by only one database request. In a real-world scenario, a transaction typically involves multiple database requests to perform a series of operations. These operations may include retrieving data, updating records, inserting new data, or deleting existing data. By grouping these requests together as a single transaction, it ensures that all the operations either succeed or fail together, maintaining the integrity and consistency of the database. Therefore, the correct answer is False.

Explanation

Most real-world database transactions are not formed by only one database request. In a real-world scenario, a transaction typically involves multiple database requests to perform a series of operations. These operations may include retrieving data, updating records, inserting new data, or deleting existing data. By grouping these requests together as a single transaction, it ensures that all the operations either succeed or fail together, maintaining the integrity and consistency of the database. Therefore, the correct answer is False.

49. All SQL commands must be issued on a single line.

True

False

This statement is false. In SQL, commands can be issued on multiple lines for better readability and organization. SQL statements can also be broken down into multiple lines using line breaks and indentation without affecting the execution of the command. Therefore, it is not necessary to issue all SQL commands on a single line.

Explanation

This statement is false. In SQL, commands can be issued on multiple lines for better readability and organization. SQL statements can also be broken down into multiple lines using line breaks and indentation without affecting the execution of the command. Therefore, it is not necessary to issue all SQL commands on a single line.

50. 31. All changes in a table structure are made using the _____ TABLE command, followed by a keyword that produces the specific changes a user wants to make.

ALTER

COMMIT

UPDATE

ROLLBACK

The correct answer is ALTER. In database management, the ALTER TABLE command is used to make changes to the structure of a table. It allows users to add, modify, or delete columns, as well as define constraints and indexes. The ALTER TABLE command is followed by a keyword that specifies the specific change the user wants to make, such as ADD, MODIFY, or DROP.

Explanation

The correct answer is ALTER. In database management, the ALTER TABLE command is used to make changes to the structure of a table. It allows users to add, modify, or delete columns, as well as define constraints and indexes. The ALTER TABLE command is followed by a keyword that specifies the specific change the user wants to make, such as ADD, MODIFY, or DROP.

51. 44. A(n) _____ phase in a two phase lock is when a transaction releases all locks and cannot obtain a new lock.

Growing

Shrinking

Locking

Unlocking

In a two-phase lock, the shrinking phase refers to the point in a transaction where all locks held by the transaction are released, and the transaction is unable to acquire any new locks. This phase occurs when a transaction is in the process of completing or finishing, and it signifies that the transaction is gradually releasing its hold on the resources it had acquired during its execution. During the shrinking phase, the transaction is still active but is no longer acquiring any new locks.

Explanation

In a two-phase lock, the shrinking phase refers to the point in a transaction where all locks held by the transaction are released, and the transaction is unable to acquire any new locks. This phase occurs when a transaction is in the process of completing or finishing, and it signifies that the transaction is gradually releasing its hold on the resources it had acquired during its execution. During the shrinking phase, the transaction is still active but is no longer acquiring any new locks.

52. 39. The special operator used to check whether an attribute value ro string pattern is _____.

BETWEEN

IS NULL

LIKE

IN

The special operator used to check whether an attribute value matches a string pattern is "LIKE". This operator is commonly used in SQL queries to perform pattern matching on string values. It allows for the use of wildcard characters such as "%" to represent any number of characters, and "_" to represent a single character. By using the "LIKE" operator, you can search for specific patterns within attribute values in a database.

Explanation

The special operator used to check whether an attribute value matches a string pattern is "LIKE". This operator is commonly used in SQL queries to perform pattern matching on string values. It allows for the use of wildcard characters such as "%" to represent any number of characters, and "_" to represent a single character. By using the "LIKE" operator, you can search for specific patterns within attribute values in a database.

53. 26. The _____ processor is the software component found in each computer that requests data. It receives and processes the application's data requests.

Database

Transaction

Data

Network

The transaction processor is the software component found in each computer that requests data. It receives and processes the application's data requests.

Explanation

The transaction processor is the software component found in each computer that requests data. It receives and processes the application's data requests.

54. 28. Of the following events, which is defined by ANSI as being equivalent to a ROLLBACK?

Five SQL statements are executed.

The end of a program is successfully reached.

All changes are aborted and returned to a previous consistent state.

The database is shut down for maintenance.

The correct answer is "All changes are aborted and returned to a previous consistent state." This event is defined by ANSI as being equivalent to a ROLLBACK. When this event occurs, any changes made to the database since the last savepoint or transaction commit are undone and the database is returned to a previous consistent state. This is similar to the rollback operation in SQL, which allows for the cancellation of a transaction and the restoration of the database to its previous state.

Explanation

The correct answer is "All changes are aborted and returned to a previous consistent state." This event is defined by ANSI as being equivalent to a ROLLBACK. When this event occurs, any changes made to the database since the last savepoint or transaction commit are undone and the database is returned to a previous consistent state. This is similar to the rollback operation in SQL, which allows for the cancellation of a transaction and the restoration of the database to its previous state.

55. 14. You cannot insert a row containing a null attribute value using SQL.

True

False

In SQL, it is possible to insert a row containing a null attribute value. The NULL value represents missing or unknown data, and it is allowed to be inserted into a table. Therefore, the statement "You cannot insert a row containing a null attribute value using SQL" is false.

Explanation

In SQL, it is possible to insert a row containing a null attribute value. The NULL value represents missing or unknown data, and it is allowed to be inserted into a table. Therefore, the statement "You cannot insert a row containing a null attribute value using SQL" is false.

56. 16. The conditional LIKE must be used in conjunction with wildcard characters.

True

False

Option 3

Option 4

The statement is true because the LIKE operator is used in SQL to perform pattern matching on a specified column. Wildcard characters, such as % and _, are used with the LIKE operator to represent unknown or multiple characters. Without the use of wildcard characters, the LIKE operator would not be able to match patterns effectively. Therefore, the conditional LIKE must be used in conjunction with wildcard characters to achieve the desired pattern matching functionality.

Explanation

The statement is true because the LIKE operator is used in SQL to perform pattern matching on a specified column. Wildcard characters, such as % and _, are used with the LIKE operator to represent unknown or multiple characters. Without the use of wildcard characters, the LIKE operator would not be able to match patterns effectively. Therefore, the conditional LIKE must be used in conjunction with wildcard characters to achieve the desired pattern matching functionality.

57. 50. No matter what language you use, if it contains embedded SQL statements, it is called the _____ language.

Base

Static

Host

View

The term "host" refers to the language that is used as the main programming language, which can be any language, as long as it contains embedded SQL statements. In other words, regardless of the specific programming language being used, if it includes embedded SQL statements, it is referred to as the host language.

Explanation

The term "host" refers to the language that is used as the main programming language, which can be any language, as long as it contains embedded SQL statements. In other words, regardless of the specific programming language being used, if it includes embedded SQL statements, it is referred to as the host language.

58. 14. A shared lock produces no conflict as long as all the concurrent transactions are read-write only.

True

False

A shared lock does not produce conflicts only when all concurrent transactions are read-only. If any concurrent transaction is performing a write operation, it can cause conflicts with other transactions holding a shared lock, as write operations require exclusive access to the data. Therefore, the statement is false.

Explanation

A shared lock does not produce conflicts only when all concurrent transactions are read-only. If any concurrent transaction is performing a write operation, it can cause conflicts with other transactions holding a shared lock, as write operations require exclusive access to the data. Therefore, the statement is false.

59. 22. _____ requires that all operations of a transaction be completed.

Specificity

Atomicity

Durability

Time stamping

Atomicity refers to the property of a transaction in which all operations within the transaction must be completed successfully, or none of them should be executed at all. It ensures that if any part of a transaction fails, the entire transaction is rolled back, and the database remains unchanged. This guarantees the consistency and integrity of the database, as incomplete or partially executed transactions are not allowed. Therefore, atomicity is the correct answer as it requires all operations of a transaction to be completed.

Explanation

Atomicity refers to the property of a transaction in which all operations within the transaction must be completed successfully, or none of them should be executed at all. It ensures that if any part of a transaction fails, the entire transaction is rolled back, and the database remains unchanged. This guarantees the consistency and integrity of the database, as incomplete or partially executed transactions are not allowed. Therefore, atomicity is the correct answer as it requires all operations of a transaction to be completed.

60. 38. A _____ lock will lock the entire diskpage.

Transaction-level

Table-level

Page-level

Row-level

A page-level lock will lock the entire disk page, meaning that any changes made to any data within that page will be locked and inaccessible to other transactions or processes. This type of lock ensures data integrity and prevents conflicts or inconsistencies that could occur if multiple transactions were allowed to access and modify the same page simultaneously.

Explanation

A page-level lock will lock the entire disk page, meaning that any changes made to any data within that page will be locked and inaccessible to other transactions or processes. This type of lock ensures data integrity and prevents conflicts or inconsistencies that could occur if multiple transactions were allowed to access and modify the same page simultaneously.

61. 9. Distributed processing does not require a distributed database, and a distributed database does not require distributed processing.

True

False

Distributed processing refers to the use of multiple computers or processors working together to perform a task. In this context, a distributed database is not necessary for distributed processing to occur. On the other hand, a distributed database is a database that is spread across multiple computers or locations. While distributed processing can occur without a distributed database, a distributed database does require distributed processing in order to function properly. Therefore, the statement that distributed processing does not require a distributed database, and a distributed database does not require distributed processing is false.

Explanation

Distributed processing refers to the use of multiple computers or processors working together to perform a task. In this context, a distributed database is not necessary for distributed processing to occur. On the other hand, a distributed database is a database that is spread across multiple computers or locations. While distributed processing can occur without a distributed database, a distributed database does require distributed processing in order to function properly. Therefore, the statement that distributed processing does not require a distributed database, and a distributed database does not require distributed processing is false.

62. 41. The _____ pseudo-column is used to select the next value from a sequence.

CURRVAL

NEXTVAL

The correct answer is "NEXTVAL". In Oracle, a sequence is an object that generates a sequence of unique numbers. The "NEXTVAL" pseudo-column is used to select the next value from a sequence. It retrieves the next value of the sequence and increments it for the next retrieval. This allows you to generate unique identifiers for rows in a table or to generate primary key values.

Explanation

The correct answer is "NEXTVAL". In Oracle, a sequence is an object that generates a sequence of unique numbers. The "NEXTVAL" pseudo-column is used to select the next value from a sequence. It retrieves the next value of the sequence and increments it for the next retrieval. This allows you to generate unique identifiers for rows in a table or to generate primary key values.

63. 26. ANSI has defined standards that govern SQL database transactions. Transaction support is provided by two SQL statements _____ and ROLLBACK.

RETRIEVE

ASSIGN

UPDATE

COMMIT

ANSI has defined standards that govern SQL database transactions. Transaction support is provided by two SQL statements COMMIT and ROLLBACK. The COMMIT statement is used to permanently save the changes made in a transaction, whereas the ROLLBACK statement is used to undo the changes made in a transaction. Therefore, the correct answer is COMMIT.

Explanation

ANSI has defined standards that govern SQL database transactions. Transaction support is provided by two SQL statements COMMIT and ROLLBACK. The COMMIT statement is used to permanently save the changes made in a transaction, whereas the ROLLBACK statement is used to undo the changes made in a transaction. Therefore, the correct answer is COMMIT.

64. 38. The tables on which a view, or a virtual table derived from a SELECT query, are based are called _____ tables.

Indexed

Core

Relation

Base

The tables on which a view or a virtual table derived from a SELECT query are based are called "base" tables. These base tables serve as the underlying source of data for the view or virtual table, providing the necessary information for the view to retrieve and display the desired data.

Explanation

The tables on which a view or a virtual table derived from a SELECT query are based are called "base" tables. These base tables serve as the underlying source of data for the view or virtual table, providing the necessary information for the view to retrieve and display the desired data.

65. 47. Oracle recommends _____ for creating audit logs.

Triggers

Stored procedures

Stored functions

Tables

Oracle recommends using triggers for creating audit logs because triggers are database objects that can be automatically executed in response to specific events, such as insert, update, or delete operations on a table. By using triggers, developers can capture and log the changes made to the data in the database, providing a reliable and efficient way to track and monitor the audit trail. Stored procedures and functions can also be used for this purpose, but triggers are specifically designed for this task and are the recommended approach by Oracle.

Explanation

Oracle recommends using triggers for creating audit logs because triggers are database objects that can be automatically executed in response to specific events, such as insert, update, or delete operations on a table. By using triggers, developers can capture and log the changes made to the data in the database, providing a reliable and efficient way to track and monitor the audit trail. Stored procedures and functions can also be used for this purpose, but triggers are specifically designed for this task and are the recommended approach by Oracle.

66. 23. A distributed database is composed of several parts known as database _____.

Sections

Fragments

Partitions

Parts

A distributed database is composed of several parts known as database fragments. Fragments are subsets of the database that are distributed across multiple nodes or servers in a network. Each fragment contains a portion of the data and schema of the entire database. This fragmentation allows for improved performance, scalability, and fault tolerance in distributed systems. By dividing the database into fragments, different parts of the database can be stored and accessed in parallel, increasing efficiency and reducing the load on individual nodes.

Explanation

A distributed database is composed of several parts known as database fragments. Fragments are subsets of the database that are distributed across multiple nodes or servers in a network. Each fragment contains a portion of the data and schema of the entire database. This fragmentation allows for improved performance, scalability, and fault tolerance in distributed systems. By dividing the database into fragments, different parts of the database can be stored and accessed in parallel, increasing efficiency and reducing the load on individual nodes.

67. 44. Which is a feature of a correlated subquery?

The inner subquery executes first.

The outer subquery initiates the process of execution in a subquery.

The inner subquery initiates the process of execution in a subquery.

The outer subquery executes independent of the inner subquery.

A correlated subquery is a subquery that depends on the outer query for its values. In this case, the outer subquery initiates the process of execution in a subquery, meaning that the outer query is executed first and then the subquery is executed for each row returned by the outer query. This allows the subquery to access and use the values from the outer query in its execution. Therefore, the feature of a correlated subquery is that the outer subquery initiates the process of execution in a subquery.

Explanation

A correlated subquery is a subquery that depends on the outer query for its values. In this case, the outer subquery initiates the process of execution in a subquery, meaning that the outer query is executed first and then the subquery is executed for each row returned by the outer query. This allows the subquery to access and use the values from the outer query in its execution. Therefore, the feature of a correlated subquery is that the outer subquery initiates the process of execution in a subquery.

68. 27. Of the following events, which is defined by ANSI as being equivalent to a COMMIT?

Five SQL statements are executed.

The end of a program is successfully reached.

The program is abnormally terminated.

The database is shut down for maintenance.

The end of a program is successfully reached is defined by ANSI as being equivalent to a COMMIT because it signifies that all the changes made to the database during the program's execution should be permanently saved. This ensures data integrity and consistency, as any changes made are only committed when the program successfully completes its execution.

Explanation

The end of a program is successfully reached is defined by ANSI as being equivalent to a COMMIT because it signifies that all the changes made to the database during the program's execution should be permanently saved. This ensures data integrity and consistency, as any changes made are only committed when the program successfully completes its execution.

69. 34. _____ are required to prevent another transaction form reading inconsistent data.

Locks

Schedules

Stampts

Logs

Locks are required to prevent another transaction from reading inconsistent data. Locks ensure that only one transaction can access a particular piece of data at a time, preventing concurrent transactions from accessing and modifying the same data simultaneously. By acquiring locks on data items, transactions can ensure data consistency and avoid conflicts that may arise due to concurrent access. Therefore, locks play a crucial role in maintaining data integrity and preventing inconsistencies in a multi-user database system.

Explanation

Locks are required to prevent another transaction from reading inconsistent data. Locks ensure that only one transaction can access a particular piece of data at a time, preventing concurrent transactions from accessing and modifying the same data simultaneously. By acquiring locks on data items, transactions can ensure data consistency and avoid conflicts that may arise due to concurrent access. Therefore, locks play a crucial role in maintaining data integrity and preventing inconsistencies in a multi-user database system.

70. 43. In Oracle, _____ make(s) it possible to merge SQL and traditional programming constructs, such as variables, conditional processing (IF-THEN-ELSE), basic loops (FOR and WHILE loops,) and error trapping.

Dynamic SQL

Stored procedures

Embedded SQL

Procedural Language SQL

Procedural Language SQL in Oracle allows for the integration of SQL and traditional programming constructs, such as variables, conditional processing (IF-THEN-ELSE), basic loops (FOR and WHILE loops), and error trapping. This enables developers to write more complex and dynamic SQL statements within their code, providing greater flexibility and control over the execution of SQL queries.

Explanation

Procedural Language SQL in Oracle allows for the integration of SQL and traditional programming constructs, such as variables, conditional processing (IF-THEN-ELSE), basic loops (FOR and WHILE loops), and error trapping. This enables developers to write more complex and dynamic SQL statements within their code, providing greater flexibility and control over the execution of SQL queries.

71. An alias cannot be used when a table is required to be joined to itself in a recursive query.

True

False

In a recursive query, a table can be joined to itself using an alias. This allows the query to refer to the same table multiple times within the same query. This is commonly used in situations where the query needs to reference different rows within the same table in order to perform calculations or retrieve specific data. Therefore, the statement "An alias cannot be used when a table is required to be joined to itself in a recursive query" is false.

Explanation

In a recursive query, a table can be joined to itself using an alias. This allows the query to refer to the same table multiple times within the same query. This is commonly used in situations where the query needs to reference different rows within the same table in order to perform calculations or retrieve specific data. Therefore, the statement "An alias cannot be used when a table is required to be joined to itself in a recursive query" is false.

72. 5. Serializability means that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed.

True

False

Serializability means that the execution of concurrent transactions produces the same result as if the transactions were executed serially, one after the other. It ensures that the final state of the database is consistent and preserves the integrity of the data. However, it does not mean that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed. Multiple transactions can access and manipulate the same data concurrently, as long as the overall execution remains serializable.

Explanation

Serializability means that the execution of concurrent transactions produces the same result as if the transactions were executed serially, one after the other. It ensures that the final state of the database is consistent and preserves the integrity of the data. However, it does not mean that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed. Multiple transactions can access and manipulate the same data concurrently, as long as the overall execution remains serializable.

73. 45. The PL/SQL block starts with the _____ section.

IS

OPEN

DECLARE

BEGIN

The PL/SQL block starts with the DECLARE section. This section is used to declare variables, cursors, and other program objects that will be used within the block. It is where the programmer specifies the data types and initial values of the variables. Once the variables are declared, they can be used in the subsequent sections of the block, such as the BEGIN section where the actual logic of the program is written.

Explanation

The PL/SQL block starts with the DECLARE section. This section is used to declare variables, cursors, and other program objects that will be used within the block. It is where the programmer specifies the data types and initial values of the variables. Once the variables are declared, they can be used in the subsequent sections of the block, such as the BEGIN section where the actual logic of the program is written.

74. 29. The implicit beginning of a transaction is when _____.

A database is started

A table is accessed for the first time

The first SQL statement is encountered

The COMMIT command is issued

The implicit beginning of a transaction is when the first SQL statement is encountered. This means that whenever a SQL statement is executed, a transaction is automatically started. This allows for multiple SQL statements to be executed as part of a single transaction, ensuring that all changes made by the statements are either committed or rolled back together.

Explanation

The implicit beginning of a transaction is when the first SQL statement is encountered. This means that whenever a SQL statement is executed, a transaction is automatically started. This allows for multiple SQL statements to be executed as part of a single transaction, ensuring that all changes made by the statements are either committed or rolled back together.

75. 40. Which statement describes a feature of Oracle sequences?

Oracle sequences are tied to columns and tables.

Oracle sequences generate a character string that can be assigned to tables.

An Oracle sequence uses the identity column property to automatically number rows.

Dropping a sequence does not delete values assigned to table attributes; it deletes only the sequence object from the database.

An Oracle sequence is a database object that generates unique numbers. When a sequence is dropped, it only removes the sequence object from the database and does not delete the values that have been assigned to table attributes using the sequence. This means that even if the sequence is dropped, the previously generated values will still remain assigned to the table attributes.

Explanation

An Oracle sequence is a database object that generates unique numbers. When a sequence is dropped, it only removes the sequence object from the database and does not delete the values that have been assigned to table attributes using the sequence. This means that even if the sequence is dropped, the previously generated values will still remain assigned to the table attributes.

76. 11. A lock guarantees the open use of a data item to multiple transactions.

True

False

A lock does not guarantee the open use of a data item to multiple transactions. In fact, a lock is used to restrict access to a data item, ensuring that only one transaction can access it at a time. This is done to prevent conflicts and maintain data integrity. Therefore, the statement is false.

Explanation

A lock does not guarantee the open use of a data item to multiple transactions. In fact, a lock is used to restrict access to a data item, ensuring that only one transaction can access it at a time. This is done to prevent conflicts and maintain data integrity. Therefore, the statement is false.

77. 46. The _____ approach to scheduling concurrent transactions assigns a global unique stamp to each transaction.

Scheduled

Table-locking

Unique

Time stamping

The time stamping approach to scheduling concurrent transactions assigns a global unique stamp to each transaction. This helps in determining the order in which transactions should be executed and ensures that conflicts and inconsistencies are avoided.

Explanation

The time stamping approach to scheduling concurrent transactions assigns a global unique stamp to each transaction. This helps in determining the order in which transactions should be executed and ensures that conflicts and inconsistencies are avoided.

78. 30. A(n) _____ join will select only the rows with matching values in the common attribute(s).

Natural

Outer

Full

Cross

A natural join will select only the rows with matching values in the common attribute(s). This means that it will combine the rows from two tables based on the values in the common attribute(s), and only include the rows where the values match.

Explanation

A natural join will select only the rows with matching values in the common attribute(s). This means that it will combine the rows from two tables based on the values in the common attribute(s), and only include the rows where the values match.

79. 22. Which SQL format would be best used for a small, numeric data type?

INTEGER

SMALLINT

NUMERIC(L,D)

CHAR(L)

SMALLINT would be the best SQL format to use for a small, numeric data type. This data type is specifically designed to store small integer values, typically ranging from -32,768 to 32,767. It requires less storage space compared to INTEGER or NUMERIC data types, making it ideal for small numeric values. CHAR(L) is not suitable for numeric data types as it is used for storing character data, while NUMERIC(L,D) is used for storing decimal numbers and may not be necessary for small numeric values.

Explanation

SMALLINT would be the best SQL format to use for a small, numeric data type. This data type is specifically designed to store small integer values, typically ranging from -32,768 to 32,767. It requires less storage space compared to INTEGER or NUMERIC data types, making it ideal for small numeric values. CHAR(L) is not suitable for numeric data types as it is used for storing character data, while NUMERIC(L,D) is used for storing decimal numbers and may not be necessary for small numeric values.

80. 15. A growing phase in a two-phase lock is when a transaction acquires all the required locks without locking any data.

True

False

A growing phase in a two-phase lock is when a transaction acquires locks on data items incrementally and releases them only after acquiring all the required locks. This ensures that the transaction does not release any locks before it has acquired all the necessary locks, preventing any potential conflicts with other transactions. Therefore, the statement that a growing phase is when a transaction acquires all the required locks without locking any data is incorrect.

Explanation

A growing phase in a two-phase lock is when a transaction acquires locks on data items incrementally and releases them only after acquiring all the required locks. This ensures that the transaction does not release any locks before it has acquired all the necessary locks, preventing any potential conflicts with other transactions. Therefore, the statement that a growing phase is when a transaction acquires all the required locks without locking any data is incorrect.

81. 42. A(n) _____ lock exists when concurrent transactions are granted read access on the basis of a common lock.

Shared

Exclusive

Binary

Two-phase

A shared lock exists when concurrent transactions are granted read access on the basis of a common lock. This means that multiple transactions can access and read the same data simultaneously without interfering with each other. This type of lock is commonly used in situations where multiple users or processes need to access the same data for reading purposes only and there is no risk of data inconsistency or conflicts.

Explanation

A shared lock exists when concurrent transactions are granted read access on the basis of a common lock. This means that multiple transactions can access and read the same data simultaneously without interfering with each other. This type of lock is commonly used in situations where multiple users or processes need to access the same data for reading purposes only and there is no risk of data inconsistency or conflicts.

82. 37. A _____ lock will lock the entire table, preventing access to any row by a transaction while another transaction is using the table.

Database-level

Table-level

Page-level

Row-level

A table-level lock will lock the entire table, preventing access to any row by a transaction while another transaction is using the table. This means that no other transactions can read or modify any data in the table until the lock is released. This type of lock is useful in situations where multiple transactions need to access the same table, but it is important to ensure that only one transaction can access the table at a time to maintain data integrity.

Explanation

A table-level lock will lock the entire table, preventing access to any row by a transaction while another transaction is using the table. This means that no other transactions can read or modify any data in the table until the lock is released. This type of lock is useful in situations where multiple transactions need to access the same table, but it is important to ensure that only one transaction can access the table at a time to maintain data integrity.

83. 38. A _____ lets a single SQL statement access the data that are to be processed by a single remote database processor.

Remote request

Remote transaction

Distributed request

Distributed transaction

A remote request allows a single SQL statement to access the data that are to be processed by a single remote database processor. This means that the request is sent to a remote database server, which then processes the request and returns the results back to the client. This is different from a distributed request or distributed transaction, which involve multiple database processors working together to process the request or transaction.

Explanation

A remote request allows a single SQL statement to access the data that are to be processed by a single remote database processor. This means that the request is sent to a remote database server, which then processes the request and returns the results back to the client. This is different from a distributed request or distributed transaction, which involve multiple database processors working together to process the request or transaction.

84. 43. The special operator used to check whether a subquery returns any rows is _____.

BETWEEN

EXISTS

LIKE

IN

The special operator EXISTS is used to check whether a subquery returns any rows. It returns a boolean value of true if the subquery returns at least one row, and false if it does not. This operator is often used in combination with the WHERE clause to filter results based on the existence of related records in another table.

Explanation

The special operator EXISTS is used to check whether a subquery returns any rows. It returns a boolean value of true if the subquery returns at least one row, and false if it does not. This operator is often used in combination with the WHERE clause to filter results based on the existence of related records in another table.

85. 43. What rule applies to the two-phase locking protocol?

Two transactions cannot have conflicting lock.

No unlock operation can precede a lock operation in a different transaction.

No data is affected until the transaction is in its locked position.

The correct answer is that the two-phase locking protocol states that two transactions cannot have conflicting locks. This means that if one transaction has a lock on a certain data item, another transaction cannot have a conflicting lock on the same data item at the same time. This rule ensures that transactions do not interfere with each other and helps maintain data consistency and integrity.

Explanation

The correct answer is that the two-phase locking protocol states that two transactions cannot have conflicting locks. This means that if one transaction has a lock on a certain data item, another transaction cannot have a conflicting lock on the same data item at the same time. This rule ensures that transactions do not interfere with each other and helps maintain data consistency and integrity.

86. 4. SQL supports the conditional execution of procedures (IF-THEN-ELSE statements) that are typically supported by a programming language.

True

False

SQL does not support the conditional execution of procedures (IF-THEN-ELSE statements) like a programming language does. SQL is primarily used for managing and manipulating data in relational databases, while programming languages are used for writing code and implementing logic. SQL does have conditional statements like IF and CASE, but they are used within queries to filter and manipulate data, not for controlling the flow of execution in procedures. Therefore, the given statement is false.

Explanation

SQL does not support the conditional execution of procedures (IF-THEN-ELSE statements) like a programming language does. SQL is primarily used for managing and manipulating data in relational databases, while programming languages are used for writing code and implementing logic. SQL does have conditional statements like IF and CASE, but they are used within queries to filter and manipulate data, not for controlling the flow of execution in procedures. Therefore, the given statement is false.

87. 33. As long as two transactions, T1 and T2, access _____ data, there is no conflict, and the order of execution is irrelevant to the final outcome.

Shared

Common

Unrelated

Locked

When two transactions, T1 and T2, access unrelated data, it means that they are accessing different sets of data that do not overlap or conflict with each other. Since there is no conflict between the data accessed by these transactions, the order in which they are executed does not affect the final outcome. This means that T1 and T2 can be executed in any order without causing any inconsistencies or errors in the final result.

Explanation

When two transactions, T1 and T2, access unrelated data, it means that they are accessing different sets of data that do not overlap or conflict with each other. Since there is no conflict between the data accessed by these transactions, the order in which they are executed does not affect the final outcome. This means that T1 and T2 can be executed in any order without causing any inconsistencies or errors in the final result.

88. 39. A diskpage, or page, is the equivalent of a _____.

Database table

Disk sector

Diskblock

A diskpage, or page, is the equivalent of a diskblock. A diskblock is a fixed-size unit of data storage on a disk, typically consisting of multiple disk sectors. It is used as the basic unit for reading and writing data to and from a disk. Therefore, a diskpage can be considered as a single diskblock that contains a certain amount of data.

Explanation

A diskpage, or page, is the equivalent of a diskblock. A diskblock is a fixed-size unit of data storage on a disk, typically consisting of multiple disk sectors. It is used as the basic unit for reading and writing data to and from a disk. Therefore, a diskpage can be considered as a single diskblock that contains a certain amount of data.

89. 27. In theory, a(n) _____ can be an independent centralized database management system with proper interfaces to support remote access from other independent database management systems in the network.

Transaction processor

Application processor

Transaction manager

Data processor

A data processor can be an independent centralized database management system with proper interfaces to support remote access from other independent database management systems in the network.

Explanation

A data processor can be an independent centralized database management system with proper interfaces to support remote access from other independent database management systems in the network.

90. 39. The Oracle equivalent to an MS Access AutoNumber is a(n) _____.

Auto-number

Sequence

TO_NUMBER function

Trigger

In Oracle, a sequence is used to generate unique numbers automatically, similar to an MS Access AutoNumber. A sequence is a database object that generates a sequence of numbers, and it can be used to generate primary key values for tables. Therefore, the correct answer is "sequence".

Explanation

In Oracle, a sequence is used to generate unique numbers automatically, similar to an MS Access AutoNumber. A sequence is a database object that generates a sequence of numbers, and it can be used to generate primary key values for tables. Therefore, the correct answer is "sequence".

91. 24. _____ means that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed.

Serializability

Atomicity

Isolation

Time stamping

Isolation refers to the property in database transactions where data used during the execution of a transaction cannot be accessed or modified by any other transaction until the first transaction is completed. This ensures that each transaction is executed independently and does not interfere with other concurrent transactions, thereby maintaining data integrity and consistency.

Explanation

Isolation refers to the property in database transactions where data used during the execution of a transaction cannot be accessed or modified by any other transaction until the first transaction is completed. This ensures that each transaction is executed independently and does not interfere with other concurrent transactions, thereby maintaining data integrity and consistency.

92. 35. The _____ manager is responsible for assigning and policing the locks used by transactions.

Transaction

Database

Lock

Schedule

The lock manager is responsible for assigning and policing the locks used by transactions. This means that it controls the access to resources in a database and ensures that multiple transactions do not interfere with each other by acquiring and releasing locks. The lock manager plays a crucial role in maintaining the integrity and consistency of the database by preventing conflicts and ensuring that transactions operate in a controlled and synchronized manner.

Explanation

The lock manager is responsible for assigning and policing the locks used by transactions. This means that it controls the access to resources in a database and ensures that multiple transactions do not interfere with each other by acquiring and releasing locks. The lock manager plays a crucial role in maintaining the integrity and consistency of the database by preventing conflicts and ensuring that transactions operate in a controlled and synchronized manner.

93. 41. A(n) _____ specifically reserves access to the transaction that locked the object.

Shared lock

Exclusive lock

Binary lock

Deadlock

An exclusive lock specifically reserves access to the transaction that locked the object. This means that only the transaction that acquired the exclusive lock can access the object, and other transactions are prevented from accessing it until the exclusive lock is released. This ensures that the transaction has exclusive control over the object and can perform any necessary operations without interference from other transactions.

Explanation

An exclusive lock specifically reserves access to the transaction that locked the object. This means that only the transaction that acquired the exclusive lock can access the object, and other transactions are prevented from accessing it until the exclusive lock is released. This ensures that the transaction has exclusive control over the object and can perform any necessary operations without interference from other transactions.

94. 30. A _____ distributed database system will support different database management systems (DBMS) that may even support different models running under different computer systems.

Fully heterogeneous

Fully homogeneous

Homogeneous

Heterogeneous

A fully heterogeneous distributed database system is capable of supporting different database management systems (DBMS) that may even support different models running under different computer systems. This means that the system can handle a wide range of diverse technologies and platforms, allowing for flexibility and compatibility across various DBMS and computer systems.

Explanation

A fully heterogeneous distributed database system is capable of supporting different database management systems (DBMS) that may even support different models running under different computer systems. This means that the system can handle a wide range of diverse technologies and platforms, allowing for flexibility and compatibility across various DBMS and computer systems.

95. 24. Distributed processing does not require:

Processing function distribution to all storage sites.

An existing distributed database.

Interconnected networks of components.

Distributed processing refers to the use of multiple computers or processors to perform a task or process data. It involves distributing the processing function to different storage sites. It also requires interconnected networks of components to facilitate communication and data transfer between the different processing sites. However, it does not necessarily require an existing distributed database. Distributed processing can be used with any type of data storage or database system, whether it is distributed or not. Therefore, the correct answer is that distributed processing does not require an existing distributed database.

Explanation

Distributed processing refers to the use of multiple computers or processors to perform a task or process data. It involves distributing the processing function to different storage sites. It also requires interconnected networks of components to facilitate communication and data transfer between the different processing sites. However, it does not necessarily require an existing distributed database. Distributed processing can be used with any type of data storage or database system, whether it is distributed or not. Therefore, the correct answer is that distributed processing does not require an existing distributed database.

96. 6. Durability requires that all portions of the transaction must be treated as a single, logical unit of work in which all operations are applied and completed to produce a consistent database.

True

False

Durability does not require that all portions of the transaction must be treated as a single, logical unit of work. Durability refers to the property of a database system where once a transaction is committed, its changes are permanent and will survive any subsequent failures. It ensures that the committed data is stored safely and can be recovered in the event of a system crash or failure. However, it does not dictate how the transaction is structured or treated as a unit of work. Therefore, the statement is false.

Explanation

Durability does not require that all portions of the transaction must be treated as a single, logical unit of work. Durability refers to the property of a database system where once a transaction is committed, its changes are permanent and will survive any subsequent failures. It ensures that the committed data is stored safely and can be recovered in the event of a system crash or failure. However, it does not dictate how the transaction is structured or treated as a unit of work. Therefore, the statement is false.

97. 15. A transaction processor (TP) is the software component residing on each computer that stores and retrieves data located at the site.

True

False

A transaction processor (TP) is not the software component residing on each computer that stores and retrieves data located at the site. This statement is false.

Explanation

A transaction processor (TP) is not the software component residing on each computer that stores and retrieves data located at the site. This statement is false.

98. 28. Which query is used to list a unique value for V_CODE, where the list will produce only a list of those values that are different from one another?

SELECT ONLY V_CODEFROM PRODUCT;

SELECT UNIQUE V_CODEFROM PRODUCT;

SELECT DIFFERENT V_CODEFROM PRODUCT;

SELECT DISTINCT V_CODEFROM PRODUCT;

The correct answer is SELECT DISTINCT V_CODE FROM PRODUCT. This query uses the DISTINCT keyword to retrieve only unique values for the V_CODE column from the PRODUCT table. It will exclude any duplicate values and return a list of distinct values for V_CODE. The other options (SELECT ONLY V_CODE, SELECT UNIQUE V_CODE, SELECT DIFFERENT V_CODE) are not valid SQL syntax and will result in errors.

Explanation

The correct answer is SELECT DISTINCT V_CODE FROM PRODUCT. This query uses the DISTINCT keyword to retrieve only unique values for the V_CODE column from the PRODUCT table. It will exclude any duplicate values and return a list of distinct values for V_CODE. The other options (SELECT ONLY V_CODE, SELECT UNIQUE V_CODE, SELECT DIFFERENT V_CODE) are not valid SQL syntax and will result in errors.

99. 23. A consistent database state is one in which all _____.

Tables have foreign keys

Data integrity constraints are satisfied

Table are normalized

SQL statements only update one table at a time

A consistent database state is one in which all data integrity constraints are satisfied. This means that all the rules and conditions set on the database, such as primary key constraints, foreign key constraints, and unique constraints, are being followed and there are no violations. This ensures that the data in the database is accurate, reliable, and consistent.

Explanation

A consistent database state is one in which all data integrity constraints are satisfied. This means that all the rules and conditions set on the database, such as primary key constraints, foreign key constraints, and unique constraints, are being followed and there are no violations. This ensures that the data in the database is accurate, reliable, and consistent.

100. 6. Every PL/SQL block must be given a name.

True

False

PL/SQL blocks are not required to have a name. PL/SQL blocks are anonymous blocks of code that can be executed without being explicitly named. These blocks can be used to group and organize code, but they do not necessarily need to be named. Therefore, the statement "Every PL/SQL block must be given a name" is false.

Explanation

PL/SQL blocks are not required to have a name. PL/SQL blocks are anonymous blocks of code that can be executed without being explicitly named. These blocks can be used to group and organize code, but they do not necessarily need to be named. Therefore, the statement "Every PL/SQL block must be given a name" is false.

101. 30. The information stored in the _____ is used by the DBMS for a recovery requirement triggered by a ROLLBACK statement, a program's abnormal termination, or a system failure such as a network discrepancy or a disk crash.

Data dictionary

Metadata

Rollback manager

Transaction log

The transaction log is used by the DBMS for recovery requirements triggered by a ROLLBACK statement, a program's abnormal termination, or a system failure such as a network discrepancy or a disk crash. It records all the changes made to the database during transactions, allowing the system to undo or redo those changes as needed to maintain data consistency and integrity. The transaction log is an essential component of database recovery and ensures that the database can be restored to a consistent state in the event of failures or errors.

Explanation

The transaction log is used by the DBMS for recovery requirements triggered by a ROLLBACK statement, a program's abnormal termination, or a system failure such as a network discrepancy or a disk crash. It records all the changes made to the database during transactions, allowing the system to undo or redo those changes as needed to maintain data consistency and integrity. The transaction log is an essential component of database recovery and ensures that the database can be restored to a consistent state in the event of failures or errors.

102. 36. Lock _____ indicates the level of lock use.

Granularity

Shrinking

Growing

Serializability

Granularity refers to the level of detail or extent to which something is divided or broken down. In the context of locks, granularity indicates the level of lock use. A higher level of granularity means that locks are used at a finer level of detail, such as locking individual data items or smaller sections of code. On the other hand, a lower level of granularity means that locks are used at a broader level, such as locking entire tables or larger sections of code. Therefore, the correct answer is "granularity".

Explanation

Granularity refers to the level of detail or extent to which something is divided or broken down. In the context of locks, granularity indicates the level of lock use. A higher level of granularity means that locks are used at a finer level of detail, such as locking individual data items or smaller sections of code. On the other hand, a lower level of granularity means that locks are used at a broader level, such as locking entire tables or larger sections of code. Therefore, the correct answer is "granularity".

103. 29. _____ distributed database management systems (DDBMS) integrate multiple instances of the same DBMS over a network.

Homogeneous

Heterogeneous

Fully heterogeneous

Combination

Homogeneous distributed database management systems (DDBMS) integrate multiple instances of the same DBMS over a network. This means that all the instances of the DBMS in the distributed system are identical and have the same structure and functionality. This allows for seamless integration and sharing of data across the network. In contrast, heterogeneous DDBMS integrate multiple instances of different DBMS over a network, which can have different structures and functionalities.

Explanation

Homogeneous distributed database management systems (DDBMS) integrate multiple instances of the same DBMS over a network. This means that all the instances of the DBMS in the distributed system are identical and have the same structure and functionality. This allows for seamless integration and sharing of data across the network. In contrast, heterogeneous DDBMS integrate multiple instances of different DBMS over a network, which can have different structures and functionalities.

104. 5. A persistent stored module is stored and executed on the database client machine.

True

False

A persistent stored module is not stored and executed on the database client machine. Instead, it is stored and executed on the database server machine. The purpose of a persistent stored module is to perform specific tasks or operations within the database server itself, rather than relying on the client machine to execute them. This allows for better performance and security, as the server can handle the processing and execution of the module.

Explanation

A persistent stored module is not stored and executed on the database client machine. Instead, it is stored and executed on the database server machine. The purpose of a persistent stored module is to perform specific tasks or operations within the database server itself, rather than relying on the client machine to execute them. This allows for better performance and security, as the server can handle the processing and execution of the module.

105. 21. The SQL data manipulation command HAVING:

Restricts the selection of rows based on a conditional expression.

Restricts the selection of grouped rows based on a condition.

Modifies an attribute’s values in one or more table’s rows.

Groups the selected rows based on one or more attributes.

The SQL data manipulation command HAVING is used to restrict the selection of grouped rows based on a condition. It is used in conjunction with the GROUP BY clause to filter the results of a query based on aggregate functions or other conditions applied to grouped data. The HAVING clause is applied after the GROUP BY clause and allows you to specify conditions that must be met by the grouped rows in order to be included in the result set.

Explanation

The SQL data manipulation command HAVING is used to restrict the selection of grouped rows based on a condition. It is used in conjunction with the GROUP BY clause to filter the results of a query based on aggregate functions or other conditions applied to grouped data. The HAVING clause is applied after the GROUP BY clause and allows you to specify conditions that must be met by the grouped rows in order to be included in the result set.

106. 4. Atomicity indicates the permanence of the database's consistent state.

True

False

Atomicity does not indicate the permanence of the database's consistent state. Atomicity refers to the property of a transaction in a database system where either all the operations within the transaction are successfully completed and committed, or none of them are. It ensures that if any part of the transaction fails, the entire transaction is rolled back and the database is left unchanged. Permanence of the database's consistent state is ensured by durability, which guarantees that once a transaction is committed, its changes are permanent and will survive any subsequent failures.

Explanation

Atomicity does not indicate the permanence of the database's consistent state. Atomicity refers to the property of a transaction in a database system where either all the operations within the transaction are successfully completed and committed, or none of them are. It ensures that if any part of the transaction fails, the entire transaction is rolled back and the database is left unchanged. Permanence of the database's consistent state is ensured by durability, which guarantees that once a transaction is committed, its changes are permanent and will survive any subsequent failures.

107. 42. In subquery terminology, the first query in the SQL statement is known as the _____ query.

Outer

Left

Inner

Base

In subquery terminology, the first query in the SQL statement is known as the "outer" query. This query is used to retrieve data from the main table or dataset, and it is then used as a reference or input for the subquery. The outer query is executed first, and its results are used to filter or manipulate the data in the subquery.

Explanation

In subquery terminology, the first query in the SQL statement is known as the "outer" query. This query is used to retrieve data from the main table or dataset, and it is then used as a reference or input for the subquery. The outer query is executed first, and its results are used to filter or manipulate the data in the subquery.

Database Management Quiz: SQL and Normalization

1. 9. The scheduler establishes the order in which the operations within concurrent transactions are executed.

2.

What first name or nickname would you like us to use?

2. 6. Distributed processing shares a database's logical processing among two or more physically independent sites that are connected through a network.

3. 8. The most useful feature of PL/SQL blocks is that they let a designer create code that can be named, stored, and executed by the DBMS.

4. Although SQL commands can be grouped together on a single line, complex command sequences are best shown on separate lines, with space between the SQL command and the command's components.

5. 22. The SQL command that allows a user to permanently save data changes is _____.

6. 3. The ANSI SQL standards are also accepted by the ISO.

7. 33. SQL requires the use of the _____ command to enter data into a table.

8. A database language enables the user to perform complex queries designed to transform the raw data into useful information.

9. 2. Although the DBMS is designed to recover a database to a previous consistent state when an interruption prevents the completion of a required set of transactions, the transactions themselves are defined by the end user or programmer and must be semantically correct.

10. 1. A view is a virtual table based on a SELECT query.

11. 10. A scheduler facilitates data isolation to ensure that two transactions do not update the same data element at the same time.

12. 10. In order to manage distributed data, copies or parts of the database processing functions must be distributed to all data storage sites.

13. 11. String comparisons are made from left to right.

14. 7. In Oracle, you can use the SQL*Plus command SHOW ERRORS to help you diagnose errors found in PL/SQL blocks.

15. 23. The _____ command defines a default value for a column when no value is given.

16. 3. To remedy the lack of procedural functionality in SQL, and to provide some standardization within the many vendor offerings, the SQL-99 standard defined the use of persistent stored modules.

17. 13. SQL allows the use of logical restrictions on its inquiries such as OR, AND, and NOT.

18. 19. The COUNT function is designed to tally the number of non-null "values" of an attribute, and is often used in conjunction with the DISTINCT clause.

19. 36. Which comparison operator indicates a value is not equal?

20. 12. In a page-level lock, the DBMS will lock an entire diskpage.

21. 25. A(n) _____ query specifies which data should be retrieved and how it should be filtered, aggregated, and displayed.

22. 40. The SQL aggregate function that gives the number of rows containing non-null values for a given column is _____.

23. 35. Which command would be used to delete the table row where the P_CODE is 'BRT-345'?

24. 2. A sequence is not associated with a table and can be dropped from a database with a DROP SEQUENCE command.

25. 11. A trigger is procedural SQL code that is automatically invoked by the RDBMS upon the occurrence of a given data manipulation event.

26. 26. A(n) _____ is an alternate name given to a column or table in any SQL statement.

27. 13. A field-level lock allows concurrent transactions to access the same row, as long as they require the use of different fields within that row.

28. 40. A _____ lock allows concurrent transactions to access different rows of the same table.

29. 21. Transaction is a _____ unit of work that must be either entirely completed or aborted.

30. 32. A table can be deleted from the database by using the _____ TABLE command.

31. 28. The _____ constraint is used to validate data when an attribute value is entered.

32. 36. When a user issues the DELETE FROM tablename command without specifying a WHERE condition, _____.

33. 42. In Oracle, _____ retrieves the current value of a sequence.

34. 41. A(n) _____ is a query that is embedded (or nested) inside another query.

35. 37. The _____ command is used to restore the database to its previous condition.

36. 38. The special operator used to check whether an attribute value is within a range of values is _____.

37. 21. When you create a new database, the RDBMS automatically creates the data _____ tables in which to store the metadata and creates a default database administrator.

38. 24. The _____ specification creates an individual index on a respective attribute; use it to avoid having duplicated values in a column.

39. 30. Using the _____ command, SQL indexes can be created on the basis of any selected attribute.

40. 34. The _____ command permanently saves all changes—such as rows added, attributes modified, and rows deleted—made to any table in the database.

41. SQL is considered difficult to learn; its command set has a vocabulary of more than 300 words

42. 12. Triggers can only be used to update table values.

43. 45. A(n) _____ condition occurs when two or more transactions wait for each other to unlock data.

44. 13. The transaction processor (TP) is the software component found in each computer that requests data.

45. Comparison operators cannot be used to place restrictions on character-based attributes.

46. 24. The _____ command restricts the selection of grouped rows based on a condition.

47. The COMMIT command does not permanently save all changes. In order to do that, you must use SAVE.

48. 1. Most real-world database transactions are formed by only one database request.

49. All SQL commands must be issued on a single line.

50. 31. All changes in a table structure are made using the _____ TABLE command, followed by a keyword that produces the specific changes a user wants to make.

51. 44. A(n) _____ phase in a two phase lock is when a transaction releases all locks and cannot obtain a new lock.

52. 39. The special operator used to check whether an attribute value ro string pattern is _____.

53. 26. The _____ processor is the software component found in each computer that requests data. It receives and processes the application's data requests.

54. 28. Of the following events, which is defined by ANSI as being equivalent to a ROLLBACK?

55. 14. You cannot insert a row containing a null attribute value using SQL.

56. 16. The conditional LIKE must be used in conjunction with wildcard characters.

57. 50. No matter what language you use, if it contains embedded SQL statements, it is called the _____ language.

58. 14. A shared lock produces no conflict as long as all the concurrent transactions are read-write only.

59. 22. _____ requires that all operations of a transaction be completed.

60. 38. A _____ lock will lock the entire diskpage.

61. 9. Distributed processing does not require a distributed database, and a distributed database does not require distributed processing.

62. 41. The _____ pseudo-column is used to select the next value from a sequence.

63. 26. ANSI has defined standards that govern SQL database transactions. Transaction support is provided by two SQL statements _____ and ROLLBACK.

64. 38. The tables on which a view, or a virtual table derived from a SELECT query, are based are called _____ tables.

65. 47. Oracle recommends _____ for creating audit logs.

66. 23. A distributed database is composed of several parts known as database _____.

67. 44. Which is a feature of a correlated subquery?

68. 27. Of the following events, which is defined by ANSI as being equivalent to a COMMIT?

69. 34. _____ are required to prevent another transaction form reading inconsistent data.

70. 43. In Oracle, _____ make(s) it possible to merge SQL and traditional programming constructs, such as variables, conditional processing (IF-THEN-ELSE), basic loops (FOR and WHILE loops,) and error trapping.

71. An alias cannot be used when a table is required to be joined to itself in a recursive query.

72. 5. Serializability means that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed.

73. 45. The PL/SQL block starts with the _____ section.

74. 29. The implicit beginning of a transaction is when _____.

75. 40. Which statement describes a feature of Oracle sequences?

76. 11. A lock guarantees the open use of a data item to multiple transactions.

77. 46. The _____ approach to scheduling concurrent transactions assigns a global unique stamp to each transaction.