Evaluate the set of SQL statements: CREATE TABLE dept (deptno NUMBER(2), dname VARCHAR2(14), loc VARCHAR2(13)); ROLLBACK; DESCRIBE DEPT What is true about the set? A. The DESCRIBE DEPT statement displays the structure of the DEPT table. B. The ROLLBACK statement frees the storage space occupied by the DEPT table. C. The DESCRIBE DEPT statement returns an error ORA-04043: object DEPT does not exist. D. The DESCRIBE DEPT statement displays the structure of the DEPT table only if there is a COMMIT statement introduced before the ROLLBACK statement.

technology databases

  1. A

  2. B

  3. C

  4. D

Show answer
Correct Option: A
Explanation:

To understand the given set of SQL statements, the user must have knowledge of SQL commands and their functions.

  • CREATE TABLE statement creates a table with the specified columns and data types.

  • ROLLBACK statement rolls back the current transaction and undoes all the changes, freeing the storage space occupied by the table.

  • DESCRIBE statement displays the structure of the specified table.

Now, let's evaluate each option:

A. The DESCRIBE DEPT statement displays the structure of the DEPT table.

This option is correct. The DESCRIBE statement is used to display the structure of the specified table, and in this case, the specified table is DEPT. So, the DESCRIBE DEPT statement will display the structure of the DEPT table.

B. The ROLLBACK statement frees the storage space occupied by the DEPT table.

This option is incorrect. The ROLLBACK statement rolls back the current transaction and undoes all the changes, but it does not free the storage space occupied by the DEPT table. The table will still exist even after the ROLLBACK statement is executed.

C. The DESCRIBE DEPT statement returns an error ORA-04043: object DEPT does not exist.

This option is incorrect. The DEPT table was created using the CREATE TABLE statement, so it exists in the database. The DESCRIBE DEPT statement will display the structure of the DEPT table.

D. The DESCRIBE DEPT statement displays the structure of the DEPT table only if there is a COMMIT statement introduced before the ROLLBACK statement.

This option is incorrect. The DESCRIBE statement displays the structure of the specified table regardless of the presence of a COMMIT statement. The ROLLBACK statement undoes all the changes made in the current transaction, but it does not affect the execution of the DESCRIBE statement.

Therefore, the correct answer is:

The Answer is: A. A

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