你可能感興趣的試題

Application A holds an Update lock on a single row and application B is trying to read that row. If both applications are using isolation level UR, which of the following will occur?（）

A.Application B will read the row.
B.Applications A and B will cause a deadlock situation.
C.Application B will wait until application A releases the Update lock.
D.Application A will be terminated so that application B can read the row.

單項選擇題

Application A is designed to execute the following SQL statements within a single Unit of Work (UOW).
UPDATE employee SET salary = salary * 1.1 WHERE empno='000010' UPDATE department SET deptname = 'NEW dept' WHERE deptno='A00'Application B is designed to execute the following SQL statements within a single Unit of Work (UOW). UPDATE department SET deptname = 'OLD DEPT' WHERE deptno='A00' UPDATE employee SET salary = salary * 0.5 WHERE empno='000010'
Application A and application B execute their first SQL statement at the same time. When application A and application B try to execute their second SQL statement, a deadlock occurs.
What will happen?（）

A.The database manager will rollback the transaction in both applications.
B.The database manager will rollback the transaction in one of the two applications.
C.Application B will successfully update the EMPLOYEE and DEPARTMENT tables; Application A will be placed in a lock wait state.
D.Application A will successfully update the EMPLOYEE and DEPARTMENT tables; Application B will terminate when the lock timeout value is reached.