Database Chapters 4,5,7 Midterm 2 Quiz

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  • 1/120 Questions

    A transaction is the complete set of closely related update commands that must all be done, or none of them done, for the database to remain valid

    • True
    • False
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About This Quiz

This midterm quiz for Database Chapters 4, 5, 7 assesses key concepts in data management including nonkey attributes, primary keys, attribute meanings, and relational merging. It evaluates critical understanding and problem-solving skills in database management.

Data Management Quizzes & Trivia

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  • 2. 

    The following produce the same result: SQL> select customer_name, customer_city from customer, salesman where customer.salesman_id = salesman.salesman_id and salesman.lname = 'SMITH'; SQL> select customer_name, customer_city from customer where customer.salesman_id = (select salesman_id from salesman where lname = 'SMITH');

    • True

    • False

    Correct Answer
    A. True
    Explanation
    Both SQL queries are retrieving the same result. The first query uses a join between the customer and salesman tables to filter the results based on the salesman's last name being 'SMITH'. The second query uses a subquery to retrieve the salesman_id for the salesman with the last name 'SMITH', and then filters the customer table based on that salesman_id. Both approaches achieve the same result, so the answer is true.

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  • 3. 

    When EXISTS or NOT EXISTS is used in a subquery, the select list of the subquery will usually just select all columns as a placeholder because it doesnt matter which columns are returned

    • True

    • False

    Correct Answer
    A. True
    Explanation
    When EXISTS or NOT EXISTS is used in a subquery, the focus is on whether or not any rows exist that satisfy a certain condition. The actual data returned by the subquery is not important in this case. Therefore, the select list of the subquery will usually just select all columns as a placeholder, as the specific columns being returned do not matter. This allows the query to focus solely on the existence of the desired rows, rather than the actual data they contain.

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  • 4. 

    Persistent stored modules are extensions defined in SQL:1999 that include the capability to add and drop modules of code

    • True

    • False

    Correct Answer
    A. True
    Explanation
    Persistent stored modules are indeed extensions defined in SQL:1999 that include the capability to add and drop modules of code. These modules are stored in the database and can be accessed and executed by the database management system. They provide a way to encapsulate and organize code logic within the database, allowing for easier maintenance and reusability. This feature enhances the functionality and flexibility of SQL by enabling the creation, modification, and deletion of modules as needed. Therefore, the statement "True" is the correct answer.

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  • 5. 

    In order to find out what customers have not placed an order for a particular item, one might use the NOT qualifier along with the IN qualifier

    • True

    • False

    Correct Answer
    A. True
    Explanation
    To find out what customers have not placed an order for a particular item, using the NOT qualifier along with the IN qualifier is an effective approach. The NOT qualifier negates the condition specified in the query, while the IN qualifier checks if a value matches any of the values in a specified list. By combining these qualifiers, we can retrieve the customers who are not included in the list of customers who have ordered the particular item. Therefore, the statement is true.

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  • 6. 

    RDBMS's store database definition information in system-created tables which can be considered a data dictionary

    • True

    • False

    Correct Answer
    A. True
    Explanation
    RDBMS (Relational Database Management Systems) do store database definition information in system-created tables, which can be considered a data dictionary. This data dictionary contains metadata about the database, such as the names and types of tables, columns, constraints, and other database objects. It provides a centralized repository for storing and managing this information, allowing for easy access and maintenance of the database structure. Therefore, the statement "RDBMS's store database definition information in system-created tables which can be considered a data dictionary" is true.

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  • 7. 

    The UNION clause is used to combine the output from multiple queries into a single result table

    • True

    • False

    Correct Answer
    A. True
    Explanation
    The UNION clause is indeed used to combine the output from multiple queries into a single result table. It allows you to retrieve data from different tables or views and present it as a unified result set. The columns in the result sets of the queries must have the same data types and be in the same order. The UNION operation removes duplicate rows from the final result.

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  • 8. 

    An SQL query that implements an outer join will return rows that do not have matching values in common columns

    • True

    • False

    Correct Answer
    A. True
    Explanation
    An SQL query that implements an outer join combines rows from two or more tables, even if there are no matching values in the common columns. This means that the resulting query will include all rows from one table, and the matching rows from the other table, as well as any rows that do not have matching values in the common columns. Therefore, the statement "An SQL query that implements an outer join will return rows that do not have matching values in common columns" is true.

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  • 9. 

    The joining condition of an equi-join based upon an equality

    • True

    • False

    Correct Answer
    A. True
    Explanation
    In an equi-join, the joining condition is based upon an equality. This means that the join operation is performed by matching the values of a specified column in both tables, and only the rows with matching values are included in the result. Therefore, the statement "The joining condition of an equi-join is based upon an equality" is true.

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  • 10. 

    SQL:200n allows one to calculate linear regressions, moving averages and correlations without moving the data outside of the database

    • True

    • False

    Correct Answer
    A. True
    Explanation
    SQL:200n, a version of SQL, allows users to perform calculations such as linear regressions, moving averages, and correlations directly within the database, without the need to move the data outside. This means that users can leverage the power and efficiency of the database system to perform complex calculations and analysis on large datasets, without the need for additional tools or resources. This capability enhances the convenience and performance of data analysis tasks, making it a valuable feature for users working with SQL databases.

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  • 11. 

    Combining a table with iself results in a faster query

    • True

    • False

    Correct Answer
    A. False
    Explanation
    Combining a table with itself does not result in a faster query. In fact, it can often lead to slower performance due to the increased complexity of the query. When a table is joined with itself, it essentially duplicates the data and requires more processing power to compare and match the rows. This can result in longer execution times and decreased efficiency. Therefore, the statement is false.

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  • 12. 

    A correlated subquery is executed once for each iteration through the outer loop

    • True

    • False

    Correct Answer
    A. True
    Explanation
    A correlated subquery is a subquery that references a column from the outer query. It is executed once for each row in the outer query's result set. This means that for every iteration through the outer loop, the correlated subquery is executed. Therefore, the given statement that a correlated subquery is executed once for each iteration through the outer loop is true.

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  • 13. 

    Joining tables or using a subquery may produce the same result

    • True

    • False

    Correct Answer
    A. True
    Explanation
    Joining tables or using a subquery can produce the same result because both methods allow us to combine data from multiple tables. Joining tables involves combining rows from two or more tables based on a related column, while a subquery involves nesting one query inside another to retrieve data based on a condition. In both cases, we can obtain the desired result by selecting specific columns or applying filters. Therefore, it is true that joining tables or using a subquery can yield the same outcome.

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  • 14. 

    Designing physical files requires __________ of where and when data are used in various ways

    • Maps

    • Descriptions

    • Keys

    Correct Answer
    A. Descriptions
    Explanation
    When designing physical files, it is important to have descriptions of where and when data are used in various ways. This means that the designer needs to have a clear understanding of how the data will be accessed, manipulated, and utilized within the system. By having detailed descriptions of these aspects, the designer can ensure that the physical files are organized and structured in a way that supports efficient data management and retrieval.

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  • 15. 

    The natural join is very rarely used

    • True

    • False

    Correct Answer
    A. False
    Explanation
    The statement that the natural join is very rarely used is false. The natural join is a type of join in relational databases that combines rows from two tables based on matching values in columns with the same name and data type. It is commonly used when there is a need to combine data from multiple tables without explicitly specifying the join conditions. While other types of joins may be more commonly used in certain scenarios, the natural join still has its applications and can be a useful tool in database queries and operations.

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  • 16. 

    While triggers run automatically, ________________ do not and have to be called

    • Trapdoors

    • Routines

    • Selects

    • Updates

    Correct Answer
    A. Routines
    Explanation
    Routines do not run automatically like triggers. They need to be explicitly called or invoked in order to execute their defined set of instructions. Triggers, on the other hand, are automatically triggered by specific events or actions in the database. Therefore, the correct answer is "routines".

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  • 17. 

    A type of query that is palced within a WHERE or HAVING clause of another query is called a:

    • Master query

    • Subquery

    • Superquery

    • Multi-query

    Correct Answer
    A. Subquery
    Explanation
    A subquery is a type of query that is placed within a WHERE or HAVING clause of another query. It is used to retrieve data that is based on the results of the outer query. By using a subquery, more complex and specific conditions can be applied to filter the results of the main query. This allows for more advanced and targeted data retrieval and analysis.

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  • 18. 

    START CH 7 - Constraints are a special case of triggers

    • True

    • False

    Correct Answer
    A. True
    Explanation
    Constraints are a special case of triggers because both constraints and triggers are used to enforce certain conditions or rules in a database. However, constraints are predefined rules that are automatically enforced by the database management system, while triggers are user-defined rules that are executed automatically in response to certain events. Therefore, constraints can be seen as a specific type or subset of triggers, as they are a mechanism for enforcing rules in a database.

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  • 19. 

    When the value of one attribute (the determinant) determines the value of another attribute, it is called:

    • Functional dependency

    • Merged relation

    • Transitive dependency

    • Full dependency

    Correct Answer
    A. Functional dependency
    Explanation
    Functional dependency refers to a situation where the value of one attribute determines the value of another attribute. In other words, if we know the value of one attribute, we can determine the value of another attribute based on that. This concept is important in database design and normalization, as it helps to ensure data integrity and eliminate redundancy. Therefore, the correct answer is functional dependency.

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  • 20. 

    The __________ states that no primary key attribute may be null

    • Referential integrity constraint

    • Entity integrity rule

    • Partial specialization rule

    • Range domain rule

    Correct Answer
    A. Entity integrity rule
    Explanation
    The entity integrity rule states that no primary key attribute may be null. This means that every entity in a table must have a unique identifier (primary key) and this identifier cannot have a null value. This rule ensures that each entity in a table is uniquely identified and helps maintain the integrity and consistency of the data.

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  • 21. 

    DBA_USERS contains comments on all tables in an Oracle databse

    • True

    • False

    Correct Answer
    A. False
    Explanation
    DBA_USERS does not contain comments on all tables in an Oracle database. It is a data dictionary view that provides information about all users of the database. The comments on tables can be found in the DBA_TAB_COMMENTS view, which specifically stores comments on tables. Therefore, the correct answer is False.

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  • 22. 

    Correlated subqueries are less efficient than queries that do not use nesting

    • True

    • False

    Correct Answer
    A. True
    Explanation
    Correlated subqueries are less efficient than queries that do not use nesting because in a correlated subquery, the subquery is executed for each row of the outer query. This means that the subquery is dependent on the result of the outer query, and it needs to be executed multiple times. This can lead to slower performance and increased resource usage compared to queries that do not use nesting.

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  • 23. 

    A join operation:

    • Brings together data from two different fields

    • Causes two tables with a common domain to be combined into a single table or view

    • Causes two disparate tables to be combined into a single table or view

    • Is used to combine indexing operations

    Correct Answer
    A. Causes two tables with a common domain to be combined into a single table or view
    Explanation
    A join operation is used to combine two tables that have a common domain, meaning they share a common field or attribute. This operation allows the data from both tables to be merged into a single table or view, creating a unified dataset that includes information from both tables. By matching the values in the common field, the join operation brings together related data from the two tables, facilitating analysis and retrieval of information.

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  • 24. 

    A primary key that consists of more than one attribute is called a:

    • Foreign key

    • Composite key

    • Multivalued key

    • Cardinal key

    Correct Answer
    A. Composite key
    Explanation
    A primary key that consists of more than one attribute is called a composite key. This means that the primary key is made up of multiple columns in a table, rather than just a single column. Using a composite key allows for a more precise and unique way of identifying records in a table, as it takes into account multiple attributes to create a unique identifier.

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  • 25. 

    In which type of file is multiple key retrieval not possible

    • Hashed

    • Other options werent in PDF

    Correct Answer
    A. Hashed
    Explanation
    Multiple key retrieval is not possible in a hashed file. In a hashed file, the keys are mapped to specific locations using a hash function. This allows for quick access to individual records based on their keys. However, since the keys are transformed into specific locations, it becomes difficult to retrieve multiple keys simultaneously. In other types of files, such as indexed or sequential files, it is possible to retrieve multiple keys efficiently.

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  • 26. 

    EXISTS takes a value of false if the subquery returns an intermediate result set

    • True

    • False

    Correct Answer
    A. False
    Explanation
    The EXISTS operator in SQL returns true if the subquery returns at least one row, and false if the subquery returns an empty result set. It does not return false if the subquery returns an intermediate result set. Therefore, the given statement is incorrect.

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  • 27. 

    Dynamic SQL:

    • Is used to generate appropriate SQL code on the fly, as an application is processing

    • Is quite volatile

    • Creates a less flexible application

    Correct Answer
    A. Is used to generate appropriate SQL code on the fly, as an application is processing
    Explanation
    Dynamic SQL is a technique used to generate SQL code dynamically during runtime. It allows applications to construct and execute SQL statements based on specific conditions or user inputs. This flexibility enables developers to create more adaptable and customizable applications. Unlike static SQL, which is predefined and fixed, dynamic SQL allows for the generation of SQL code on the fly, making it suitable for scenarios where the SQL code needs to be determined at runtime.

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  • 28. 

    SQL-invoked routines can be:

    • Procedures

    • Functions

    • All of the above

    • None of the above

    Correct Answer
    A. All of the above
    Explanation
    SQL-invoked routines can be procedures or functions. Procedures are a set of SQL statements that perform a specific task and can be invoked using the CALL statement. Functions, on the other hand, return a single value and can be used in SQL statements. Therefore, both procedures and functions are examples of SQL-invoked routines, making "all of the above" the correct answer.

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  • 29. 

    When all multivalued attributes have been removed from a relation , it is said to be in:

    • First normal form

    • Second normal form

    • Boyce-Codd normal form

    • Third normal form

    Correct Answer
    A. First normal form
    Explanation
    When all multivalued attributes have been removed from a relation, it is said to be in the first normal form. This means that each attribute in the relation contains only atomic values, and there are no repeating groups or arrays of values within a single attribute. The first normal form is the basic level of normalization and ensures that the relation is free from redundancy and anomalies.

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  • 30. 

    One field or combination of fields for which more than one record may have the same combination of values is called a(n):

    • Secondary key

    • Index

    • Composite key

    • Linked key

    Correct Answer
    A. Secondary key
    Explanation
    A secondary key is a field or combination of fields in a database table that allows more than one record to have the same combination of values. It is used to provide an alternate way to uniquely identify records in addition to the primary key. This can be useful in situations where there is a need to efficiently search and retrieve data based on criteria other than the primary key.

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  • 31. 

    Explicit commands to manage transactions are needed when:

    • A transaction consists of just one SQL command

    • Multiple SQL commands must be run as part of a transaction

    • Autocommit is set to off

    • None of the above

    Correct Answer
    A. Multiple SQL commands must be run as part of a transaction
    Explanation
    Explicit commands to manage transactions are needed when multiple SQL commands must be run as part of a transaction. In a transaction, multiple SQL commands are grouped together as a single unit of work that must be executed atomically. This means that either all the commands in the transaction are executed successfully, or none of them are executed at all. To ensure this atomicity, explicit commands such as BEGIN TRANSACTION, COMMIT, and ROLLBACK are used to start, end, and undo the transaction, respectively. If there is only one SQL command or if autocommit is set to off, these explicit commands are not necessary as each command is treated as a separate transaction.

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  • 32. 

    START CH5 - A method to allow adjacent secondary memory space to contain rows from several tables is called:

    • Cluttering

    • Clustering

    • Concatenating

    • Compiling

    Correct Answer
    A. Clustering
    Explanation
    Clustering is a method that allows adjacent secondary memory space to contain rows from several tables. It involves grouping similar data together based on certain criteria, such as common attributes or values. This helps improve data retrieval and processing efficiency by reducing the need to access multiple locations in secondary memory. Clustering can be particularly beneficial in database management systems where tables with related data can be physically stored close to each other, resulting in faster query execution and improved performance.

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  • 33. 

    Distributing the rows of data into separate files is called:

    • Normalization

    • Horizontal partitioning

    • Vertical partitioning

    • File allocation

    Correct Answer
    A. Horizontal partitioning
    Explanation
    Horizontal partitioning is the correct answer because it refers to the process of distributing rows of data into separate files. This technique is commonly used in database management systems to improve performance and scalability. By dividing the data horizontally, each partition can be stored and processed independently, allowing for parallel processing and reducing the load on individual servers. Horizontal partitioning is especially useful in scenarios where the dataset is too large to fit on a single server or when different parts of the data need to be accessed or modified separately.

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  • 34. 

    All of the following are common denormalization opportunities EXCEPT:

    • Two entities with a one-to-one relationship

    • A one-to-many relationship

    • A many-to-many relationship with nonkey attributes

    • Reference data

    Correct Answer
    A. A one-to-many relationship
    Explanation
    Denormalization is a technique used in database design to improve performance by adding redundant data to eliminate the need for complex joins. In a one-to-many relationship, there is already a natural redundancy as the "one" side can be repeated multiple times in the "many" side. Therefore, denormalizing this relationship would not provide any additional benefits. However, in a one-to-one relationship, a many-to-many relationship with nonkey attributes, or with reference data, denormalization can be beneficial as it can reduce the number of joins required and improve query performance.

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  • 35. 

    A type of join where a table is joined to itself is called a(n)

    • Unary join

    • Self join

    • Unnatural join

    • Pinned join

    Correct Answer
    A. Self join
    Explanation
    A self join is a type of join where a table is joined to itself. This is useful when we want to combine rows from the same table based on a related condition. In a self join, two instances of the same table are treated as separate entities, with different aliases assigned to them. This allows us to compare and match rows within the same table, enabling us to retrieve information that relates to each other.

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  • 36. 

    An attribute (or attributes) that uniquely identifies each row in a relation is called a:

    • Column

    • Foreign field

    • Primary key

    • Duplicate key

    Correct Answer
    A. Primary key
    Explanation
    A primary key is an attribute or set of attributes that uniquely identifies each row in a relation. It ensures that there are no duplicate values in the primary key column(s) and provides a way to uniquely identify and access each row in the table. This is essential for maintaining data integrity and for establishing relationships between tables in a database.

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  • 37. 

    The smallest unit of application data recognized by system software is a:

    • Field

    • Row

    • Data type

    • Column

    Correct Answer
    A. Field
    Explanation
    A field is the smallest unit of application data recognized by system software. It refers to a single piece of information within a record or a database. For example, in a database table of student records, a field could represent the student's name, age, or ID number. Fields are used to organize and store data in a structured manner, allowing for efficient retrieval and manipulation of information.

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  • 38. 

    IF-THEN-ELSE logical processing cannot be accomplished within an SQL statement

    • True

    • False

    Correct Answer
    A. False
    Explanation
    IF-THEN-ELSE logical processing can be accomplished within an SQL statement. SQL supports conditional logic through the use of CASE statements, which allow for conditional branching based on specific conditions. The CASE statement evaluates a series of conditions and returns a result based on the first condition that is met. Therefore, it is possible to perform IF-THEN-ELSE logical processing within an SQL statement using the CASE statement.

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  • 39. 

    Which of the following is not a new data type that were added in SQL:200n

    • BIGINT

    • BIT

    • MULTISET

    • XML

    Correct Answer
    A. BIT
    Explanation
    The data types BIGINT, MULTISET, and XML were all added in SQL:200n. However, BIT is not a new data type added in SQL:200n.

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  • 40. 

    A _________ is a temporary table used in the FROM clause of an SQL query

    • Correlated subquery

    • Derived table

    • View table

    • None of the above

    Correct Answer
    A. Derived table
    Explanation
    A derived table is a temporary table that is created within the query itself and used in the FROM clause. It is not a permanent table in the database but is derived from the result of a subquery or a combination of multiple tables. It allows for complex calculations and filtering to be performed on the data before it is used in the main query.

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  • 41. 

    The entity integrity rule states that:

    • No primary key attribute can be null

    • Referential integrity must be maintained across all entities

    • Each entity must have a primary key

    • A primary key must have only one attribute

    Correct Answer
    A. No primary key attribute can be null
    Explanation
    The entity integrity rule states that no primary key attribute can be null. This means that every entity in a database must have a primary key, and this primary key cannot have a null value. The primary key is used to uniquely identify each record in a table, and having a null primary key would mean that the record cannot be uniquely identified. Therefore, it is essential to ensure that the primary key attribute is always populated with a non-null value.

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  • 42. 

    Embedded SQL consists of:

    • Hard coded SQL statements included in a program written in another language

    • SQL encapsulated inside of other SQL statments

    • SQL written into a front-end application

    • SQL translated to a lower-level language

    Correct Answer
    A. Hard coded SQL statements included in a program written in another language
    Explanation
    Embedded SQL consists of hard coded SQL statements included in a program written in another language. This means that the SQL statements are directly written within the program code of another language, such as C++, Java, or Python. The SQL statements are not separate or independent, but rather integrated into the program itself. This allows for the program to interact with a database by executing these embedded SQL statements.

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  • 43. 

    In SQL, a(n) _________ subquery is a type of subquery in which processing the inner query depends on data from the outer query

    • Correlated

    • Paired

    • Natural

    • Inner

    Correct Answer
    A. Correlated
    Explanation
    A correlated subquery is a type of subquery in SQL where the processing of the inner query depends on data from the outer query. This means that the inner query is executed repeatedly for each row of the outer query, using values from the outer query to determine the result. This allows for a more dynamic and flexible query, as the inner query can be customized based on the values of each row in the outer query.

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  • 44. 

    A rule that states that each foreign key value must match a primary key value in the other

    • Referential integrity constraint

    • Key match rule

    • Entity key group rule

    • Foreign/primary match rule

    Correct Answer
    A. Referential integrity constraint
    Explanation
    The explanation for the correct answer is that a referential integrity constraint is a rule that ensures that each foreign key value in a table must match a primary key value in another table. This constraint helps maintain the integrity and consistency of the data by preventing orphaned records or invalid references. It enforces the relationship between tables and ensures that the data remains accurate and valid.

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  • 45. 

    One disadvantage of partitioning is:

    • Simplicity

    • Remote optimization

    • Extra space and update time

    • Shorter technology spans

    Correct Answer
    A. Extra space and update time
    Explanation
    Partitioning in this context refers to dividing a system or database into smaller sections or partitions. One disadvantage of partitioning is that it requires extra space and update time. Partitioning involves creating separate storage spaces for different partitions, which can lead to increased storage requirements. Additionally, when updates or changes are made to the system, it may take longer to update each partition individually, resulting in increased update time. Therefore, the extra space and update time required are considered as a disadvantage of partitioning.

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  • 46. 

    Sensitivity testing involves:

    • Checking if data is allergic

    • Seeing how accurate data are

    • Checking to see if missing data will greatly impact results

    • None of the above

    Correct Answer
    A. Checking to see if missing data will greatly impact results
    Explanation
    Sensitivity testing involves checking to see if missing data will greatly impact results. This means that sensitivity testing is done to assess the impact of missing data on the accuracy and reliability of the results. By conducting sensitivity testing, researchers can determine the extent to which missing data can affect the validity of the findings and make necessary adjustments or considerations to ensure the accuracy of the analysis.

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  • 47. 

    All of the following are valid datatypes in Oracle 11g EXCEPT

    • Varchar2

    • Datetime

    • Blob

    • Number

    Correct Answer
    A. Datetime
    Explanation
    In Oracle 11g, the valid datatypes include varchar2, blob, and number. However, datetime is not a valid datatype in Oracle 11g.

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  • 48. 

    A key decision in the physical design process is:

    • Knowing the user base

    • Selecting structures

    • Deciding on the monitor

    • All of the above

    Correct Answer
    A. Selecting structures
    Explanation
    In the physical design process, selecting structures is a key decision because it determines the overall layout and organization of the physical components. The structures chosen will impact the efficiency, performance, and scalability of the design. By carefully selecting structures, designers can ensure that the system meets the required functionality and performance goals. This decision involves considering factors such as the type of data being processed, the relationships between different components, and the specific requirements of the system.

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  • 49. 

    All of the following are guidelines for better query design EXCEPT:

    • Understand how indexes are used in query processing

    • Use a lot of self-joins

    • Write simple queries

    • Retrieve on the data that you need

    Correct Answer
    A. Use a lot of self-joins
    Explanation
    The given answer is "use a lot of self-joins." This means that using a lot of self-joins is not a guideline for better query design. Self-joins are used to join a table with itself, and while they can be useful in certain cases, using them excessively can lead to complex and inefficient queries. Therefore, it is recommended to avoid using a lot of self-joins in order to improve query performance and maintain simplicity.

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  • Mar 20, 2023
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