Oracle Database 11g: Administration I — Question 13

Which four are true about transaction, table, and row locks in an Oracle Database? (Choose four.)

Answer options

• A. Transaction locks are released when that transaction executes a COMMIT statement
• B. DML statements lock modified tables in exclusive mode
• C. Transaction locks are released when that transaction executes a ROLLBACK statement
• D. DDL statements never lock the objects that they modify
• E. A table’s row-level locks escalate to table locks when a majority of rows in that table are locked in exclusive mode
• F. SELECT statements are never blocked by row-level locks
• G. DML statements lock modified rows in exclusive mode

Correct answer: B, C, F, G

Explanation

The correct options (B, C, F, G) accurately describe the behavior of locks in Oracle Database. Option B is true as DML operations do lock tables in exclusive mode. Option C is also correct because transaction locks are released upon a ROLLBACK. Option F is right since SELECT statements are not hindered by row-level locks. Option G correctly states that DML operations lock modified rows exclusively. Options A, D, and E are incorrect as they misrepresent the locking behavior.