PL/SQL User's Guide and Reference Release 2 (9.2) Part Number A96624-01 |
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PL/SQL Language Elements, 19 of 52
You use the EXIT
statement to exit a loop. The EXIT
statement has two forms: the unconditional EXIT
and the conditional EXIT
WHEN
. With either form, you can name the loop to be exited. For more information, see "Iterative Control: LOOP and EXIT Statements".
This is an expression that yields the Boolean value TRUE
, FALSE
, or NULL
. It is evaluated with each iteration of the loop in which the EXIT
WHEN
statement appears. If the expression yields TRUE
, the current loop (or the loop labeled by label_name
) is exited immediately. For the syntax of boolean_expression
, see "Expressions".
An unconditional EXIT
statement (that is, one without a WHEN
clause) exits the current loop immediately. Execution resumes with the statement following the loop.
This identifies the loop to be exited. You can exit not only the current loop but any enclosing labeled loop.
The EXIT
statement can be used only inside a loop. PL/SQL lets you code an infinite loop. For example, the following loop will never terminate normally:
WHILE TRUE LOOP ... END LOOP;
In such cases, you must use an EXIT
statement to exit the loop.
If you use an EXIT
statement to exit a cursor FOR
loop prematurely, the cursor is closed automatically. The cursor is also closed automatically if an exception is raised inside the loop.
The EXIT
statement in the following example is not allowed because you cannot exit from a block directly; you can exit only from a loop:
DECLARE amount NUMBER; maximum NUMBER; BEGIN ... BEGIN ... IF amount >= maximum THEN EXIT; -- not allowed; use RETURN instead END IF; END;
The following loop normally executes ten times, but it will exit prematurely if there are less than ten rows to fetch:
FOR i IN 1..10 LOOP FETCH c1 INTO emp_rec; EXIT WHEN c1%NOTFOUND; total_comm := total_comm + emp_rec.comm; END LOOP;
The following example illustrates the use of loop labels:
<<outer>> FOR i IN 1..10 LOOP ... <<inner>> FOR j IN 1..100 LOOP ... EXIT outer WHEN ... -- exits both loops END LOOP inner; END LOOP outer;
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