Oracle PL/SQL Programming: A Developer's Workbook

Intermediate

Q:
11-10.	PL/SQL offers the concept of a savepoint to allow you to roll back selectively, which is the same as saving selectively, when you think about it.
Q:
11-11.	Here is a suggested exception section: EXCEPTION WHEN OTHERS THEN myerr := SQLCODE; ROLLBACK to log_savepoint; INSERT INTO log VALUES (SYSDATE, USER, myerr); SAVEPOINT log_savepoint; END;
Q:
11-12.	You receive an error: SQL> 1 BEGIN 2 ROLLBACK TO nonexistent_sp; 3 END; 4 / BEGIN * ERROR at line 1: ORA-01086: savepoint 'NONEXISTENT_SP' never established
Q:
11-13.	There are two possible approaches: Maintain your own stack of savepoints issued in your session and check the savepoint name against this stack before you issue a ROLLBACK TO command. This is rather complicated. Build a PL/SQL block around your ROLLBACK TO command and trap the ORA-01086 error if it occurs. Here is a block of code that demonstrates the second technique: EXCEPTION WHEN OTHERS THEN BEGIN ROLLBACK to log_savepoint; EXCEPTION WHEN OTHERS THEN IF SQLCODE = -1086 THEN /* Can't use savepoint, so roll all the way back. */ ROLLBACK; ELSE /* Re-raise exeption. Who knows what went wrong! */ RAISE; END IF; END; END;
Q:
11-14.	Ten savepoints were set, but only one savepoint is “active” at any time. A total of nine rows are inserted. If you issue a new savepoint with the same name as an “old” (previously set) savepoint, the new savepoint completely replaces any others with that same name. In this block of code, the same savepoint is set 10 times, so there is really ...