( : , , ,
)
10.
( ROWID)
DELETE FROM EMP E
WHERE E.ROWID > (SELECT MIN(X.ROWID)
FROM EMP X WHERE X.EMP_NO = E.EMP_NO);
11. TRUNCATE DELETE
, , (rollback segments ) .
COMMIT ,ORA CLE (
)
TRUNCATE , . , .
, .
( : TRUNCATE ,TRUNCATE DDL DML)
12. COMMIT
, COMMIT, , COMMIT
:
COMMIT :
a. .
b.
c. redo log buffer
d. ORACLE 3
( : COMMIT ,
)
ORACLE SQL ()
13.
, count(*) count(1) , ,
. COUNT(EMPNO)
( : CSDN , , , ,
)
14. Where HA VING
HA VING , HA VING .
, . WHERE , . :