1z0-071 Exam Dumps - Oracle Database 12c SQL

For the provided DELETE statement with an EXISTS clause:

Option B: The subquery is executed before the DELETE statement is executed.

Subqueries with EXISTS are typically executed before the outer DELETE statement to determine which rows of the outer query satisfy the condition.

Option D: The DELETE statement executes successfully even if the subquery selects multiple rows.

The EXISTS condition is used to check for the existence of rows returned by the subquery, regardless of how many rows there are. It returns TRUE if the subquery returns at least one row.

Options A, C, and E are incorrect because:

Option A: This statement is incorrect; the subquery is indeed a correlated subquery because it references the employee_id from the outer query (employees).

Option C: This is incorrect because not all existing rows in the EMPLOYEES table will be deleted, only those for which an associated record exists in the emp_history table.

Option E: While technically the subquery may be evaluated multiple times, it is only executed for those rows in EMPLOYEES that satisfy the condition of the EXISTS clause.