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How to: |
The BEGIN/ENDBEGIN construction enables you to issue a set of commands. Because you can use this construction anywhere an individual Maintain Data command can be used, you can use a set of commands where before you could issue only one command. For example, it can follow ON MATCH, ON NOMATCH, ON NEXT, ON NONEXT, or IF.
The syntax for the BEGIN command is
BEGIN command . . . ENDBEGIN
where:
Specifies the start of a BEGIN/ENDBEGIN block.
Note: You cannot assign a label to a BEGIN/ENDBEGIN block of code or execute it outside the bounds of the BEGIN/ENDBEGIN construction in a procedure.
Is one or more Maintain Data commands, except for CASE, DECLARE, DESCRIBE, END, MAINTAIN, and MODULE. BEGIN blocks can be nested, allowing you to place BEGIN and ENDBEGIN commands between BEGIN and ENDBEGIN commands.
Specifies the end of a BEGIN block.
The following example illustrates a block of code that executes when MATCH is successful:
MATCH Emp_ID
ON MATCH BEGIN
COMPUTE Curr_Sal = Curr_Sal * 1.05;
UPDATE Curr_Sal;
COMMIT;
ENDBEGINThe following example shows BEGIN and ENDBEGIN with ON NEXT:
ON NEXT BEGIN TYPE "Next successful."; COMPUTE New_Sal = Curr_Sal * 1.05; PERFORM Cleanup; ENDBEGIN
You can also use BEGIN and ENDBEGIN with IF to run a set of commands depending on how an expression is evaluated. In the following example, BEGIN and ENDBEGIN are used with IF and FocError to run a series of commands when the prior command fails:
IF FocError NE 0 THEN BEGIN TYPE "There was a problem."; . . . ENDBEGIN
The following example nests two BEGIN blocks. The first block starts if there is a MATCH on Emp_ID and the second block starts if UPDATE fails:
MATCH Emp_ID FROM Emps(Cnt);
ON MATCH BEGIN
TYPE "Found employee ID <Emps(Cnt).Emp_ID";
UPDATE Department Curr_Sal Curr_JobCode Ed_Hrs
FROM Emps(Cnt);
IF FocError GT 0 THEN BEGIN
TYPE "Was not able to update the data source.";
PERFORM Errorhnd;
ENDBEGIN
ENDBEGIN