Oracle PL/SQL Tutorial/PL SQL Statements/GOTO — различия между версиями
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Текущая версия на 10:05, 26 мая 2010
Содержание
An Example of the GOTO Statement
SQL> DECLARE
2 v_Status NUMBER := 1;
3 BEGIN
4 IF v_Status = 1 THEN
5 GOTO mybranch;
6 ELSE
7 v_Status := 1;
8 END IF;
9 <<mybranch>>
10 NULL;
11 END;
12 /
PL/SQL procedure successfully completed.
SQL>
Demonstrate GOTO
SQL>
SQL>
SQL> SET SERVEROUTPUT ON
SQL> BEGIN
2 DBMS_OUTPUT.PUT_LINE("BEGINNING OF BLOCK");
3
4 GOTO l_Last_Line;
5
6 DBMS_OUTPUT.PUT_LINE("GOTO didn""t work!");
7 RETURN;
8 <<l_Last_Line>>
9 DBMS_OUTPUT.PUT_LINE("Last Line");
10 END;
11 /
BEGINNING OF BLOCK
Last Line
PL/SQL procedure successfully completed.
SQL>
FOR LOOP with label
SQL>
SQL> set serveroutput on
SQL> set echo on
BEGIN
FOR v_loopcounter IN 1..5 LOOP
<<insideloop>>
DBMS_OUTPUT.PUT_LINE("Loop counter is " || v_loopcounter);
GOTO insideloop;
END LOOP;
END;
/
GOTO statement
SQL>
SQL> set serveroutput on
SQL> set echo on
SQL>
DECLARE
v_Emergency_Warning VARCHAR2(50);
v_Status NUMBER := 0;
BEGIN
<<Emergency_Check>>
BEGIN
IF v_Status = 1 THEN
DBMS_OUTPUT.PUT_LINE("call PANIC(); ");
GOTO Emergency_Check;
END IF;
END;
END;
/
JUMP out of a IF statement
SQL>
SQL> set serveroutput on
SQL> set echo on
SQL>
SQL> DECLARE
2 v_Status NUMBER := 1;
3 BEGIN
4 IF v_Status = 1 THEN
5 GOTO mybranch;
6 ELSE
7 v_Status := 1;
8 END IF;
9 <<mybranch>>
10 NULL;
11 END;
12 /
PL/SQL procedure successfully completed.
SQL>
Labels and the GOTO Statement
The GOTO statement can unconditionally branches to a statement label.
Statement labels are identifiers of a block of code.
Statement labels can be accessed directly by the GOTO statement.
<<label_name>>