WDDBA Exam: Advanced Structured Query Language

1. According to the document, what is the primary goal of a DBMS?

A. To create a logical schema for data organization
B. To manage a small body of information efficiently
C. To provide mechanisms for data manipulation only
D. To provide a convenient and efficient way to store and retrieve database information

2. What is a Database-Management System (DBMS) defined as?

A. A collection of interrelated data and a set of programs to access those data
B. A single table containing all the information for an enterprise
C. A language used for writing queries
D. A tool for data backup and recovery

3. What is the logical framework that defines the structure and relationships of data in a DBMS called?

A. A wildcard
B. A transaction
C. A schema
D. An index

4. What is the purpose of the SQL `WHERE` clause?

A. To sort data in a specific order
B. To filter the results of a query based on a specified condition
C. To combine the results of two or more `SELECT` statements
D. To retrieve all columns from a table

5. Which DML statement is used to modify existing records in a table?

A. `UPDATE`
B. `SELECT`
C. `DELETE`
D. `INSERT`

6. What will happen if you use an `UPDATE` statement without a `WHERE` clause?

A. An error message will be generated.
B. No records will be updated.
C. All records of the table will be affected.
D. The table will be deleted.

7. In SQL, which two comparison operators mean "Not equal"?

A. `=` and `!=`
B. `!=` and `<>`
C. `>` and `<`
D. `IS NULL` and `NOT NULL`

8. What is the purpose of the `CREATE INDEX` statement?

A. To create a new physical table for data storage.
B. To prevent duplicate values from being inserted into a column.
C. To retrieve data from the database more quickly, without users being able to see them.
D. To define a new schema for the database.

9. Which clause is used to sort the data in a query's result set?

A. `WHERE`
B. `ORDER BY`
C. `GROUP BY`
D. `JOIN`

10. In a `WHERE` clause with multiple conditions, which operator ensures that all conditions must be true for a record to be selected?

A. `OR`
B. `LIKE`
C. `AND`
D. `ANY`

11. The `BETWEEN` operator is used to retrieve data within a specified range. What combination of operators can it replace?

A. `IN` and `NOT IN`
B. `AND` and `OR`
C. `LIKE` and `NOT LIKE`
D. `>=` and `<=`

12. Which Boolean operator is used to test for the existence of any record in a subquery?

A. `ANY`
B. `IN`
C. `NOT`
D. `EXISTS`

13. The `IN` operator is used to specify a list of values in the `WHERE` clause. What is its function?

A. To find records that do not match any value in the list. B. To find records that match any of the values in the specified list. C. To find records that are within a specific range. D. To find records with a specified pattern.

14. What are the two wildcards often used with the `LIKE` operator, and what do they represent?

A. `%` (zero, one, or multiple characters) and `_` (one, single character)
B. `*` (any number of characters) and `?` (a single character)
C. `!` (zero or more characters) and `@` (one character)
D. `$` (any character) and `^` (the start of a string)

15. How do you eliminate duplicate records from the result set of a `SELECT` statement?

A. Use the `UNION` operator.
B. Use the `WHERE` clause.
C. Use the `GROUP BY` clause.
D. Use the `DISTINCT` keyword.

16. What does a null value indicate in SQL?

A. A zero value.
B. A blank space.
C. The column has no value.
D. An invalid data type.

17. Which operator is used to test for non-empty (not null) values?

A. `IS NULL`
B. `NOT NULL`
C. `IS NOT NULL`
D. `NOT IN`

18. What is the most common type of join that selects records with matching values in a common field from two or more tables?

A. `LEFT JOIN`
B. `RIGHT JOIN`
C. `FULL OUTER JOIN`
D. `INNER JOIN`

19. Which type of join returns all records from the left table and the matching records from the right table, with `0` records from the right side if there is no match?

A. `INNER JOIN`
B. `LEFT JOIN`
C. `RIGHT JOIN`
D. `FULL OUTER JOIN`

20. What is a key requirement for using the `UNION` operator to combine the result-set of two or more `SELECT` statements?

A. The tables must have a common key.
B. The number of rows in each table must be the same.
C. The columns must have similar data types and be in the same order.
D. The `SELECT` statements must not contain a `WHERE` clause.

21. What does DCL stand for, and what is its purpose in SQL?

A. Data Control Language; used to control privilege in the database
B. Data Command Language; used to manipulate data records
C. Database Code Language; used to write queries
D. Data Catalog List; used to define the database schema

22. Which DCL command is used to take back permissions or access from a user?

A. `GRANT`
B. `REVOKE`
C. `COMMIT`
D. `ROLLBACK`

23. Which Transaction Control Language (TCL) command is used to save data permanently?

A. `COMMIT`
B. `ROLLBACK`
C. `SAVEPOINT`
D. `BEGIN`

24. What is the purpose of the `ROLLBACK` command?

A. To create a temporary save point in a transaction.
B. To restore data to the last savepoint or committed state.
C. To permanently save the data changes.
D. To begin a new transaction.

25. What set of properties ensures the concurrent execution of multiple transactions without conflict?

A. `ETL` properties
B. `SQL` properties
C. `ACID` properties
D. `DML` properties

WDDBA Exam: Advanced Structured Query Language

Exam Results