Question

I would like to write “procedures” in DB2 9.7 without defining the “CREATE PROCEDURE” -statement. Apparently this is something called “compiled” sql statement. However, I am having problems in getting valid syntax. E.g. the syntax below does not seem to work:

BEGIN
    DECLARE V_SQL VARCHAR(1024);
    SET V_SQL = 'BEGIN
    IF EXISTS(SELECT NAME FROM SYSIBM.SYSTRIGGERS WHERE NAME = ''TRIGGER_EMPLOYEE_FOR_DELETES'') THEN
    DROP TRIGGER TRIGGER_EMPLOYEE_FOR_DELETES;
    END IF;
    END;';

    PREPARE S1 FROM V_SQL;
    EXECUTE S1;
END

I have tried adding/removing “;” and statement symbol “!” but still cannot get it to work.

Answer 1

You cannot have a DROP TRIGGER statement within a compound SQL statement. See the DB2 documentation for compound SQL.

If you are able to move the IF statement outside of V_SQL, you could do something like this:

BEGIN
    DECLARE V_SQL VARCHAR(1024);
    IF EXISTS(SELECT NAME FROM SYSIBM.SYSTRIGGERS 
                  WHERE NAME = 'TRIGGER_EMPLOYEE_FOR_DELETES'
    ) THEN
        SET V_SQL = 'DROP TRIGGER TRIGGER_EMPLOYEE_FOR_DELETES;';
        PREPARE S1 FROM V_SQL;
        EXECUTE S1;
    END IF;
END

Of course, this wouldn’t work if you need to set your condition dynamically.