Evaluate the set of SQL statements: CREATE TABLE dept (deptno NUMBER(2), dname VARCNAR2(14), loc VARCNAR2(13)); ROLLBACK; DESCRIBE DEPT What is true about the set?

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

  2. The ROLLBACK statement frees the storage space occupies by the DEPT table.

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

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

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Correct Option: A

AI Explanation

To answer this question, let's go through each option to understand why it is correct or incorrect:

Option A) The DESCRIBE DEPT statement displays the structure of the DEPT table. This option is correct because the DESCRIBE statement is used to display the structure of a table, and in this case, it will display the structure of the DEPT table.

Option B) The ROLLBACK statement frees the storage space occupied by the DEPT table. This option is incorrect. The ROLLBACK statement is used to undo transactions and restore the database to the state it was in before the transaction was initiated. It does not free the storage space occupied by the table.

Option C) The DESCRIBE DEPT statement returns an error ORA-04043: object DEPT does not exist. This option is incorrect. Since the CREATE TABLE statement is executed before the DESCRIBE statement, the DEPT table will exist, and the DESCRIBE statement will be able to display its structure.

Option 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 does not depend on the presence of a COMMIT statement before the ROLLBACK statement. It will display the structure of the DEPT table regardless of whether a COMMIT statement was used or not.

The correct answer is A. The DESCRIBE DEPT statement displays the structure of the DEPT table.

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