The CREATE TRIGGER statement compiles the trigger and stores its code in the database. If a compilation error occurs, the trigger is still created, but its triggering statement fails, except in these cases:

• The trigger was created in the disabled state.

• The triggering event is AFTER STARTUP ON DATABASE.

• The triggering event is either AFTER LOGON ON DATABASE or AFTER LOGON ON SCHEMA, and someone logs on as SYSTEM.

To see trigger compilation errors, either use the SHOW ERRORS command in SQL*Plus or Enterprise Manager, or query the static data dictionary view *_ERRORS (described in Oracle Database Reference).

If a trigger does not compile successfully, then its exception handler cannot run. For an example, see "Remote Exception Handling".

If a trigger references another object, such as a subprogram or package, and that object is modified or dropped, then the trigger becomes invalid. The next time the triggering event occurs, the compiler tries to revalidate the trigger (for details, see Oracle Database Development Guide).

To recompile a trigger manually, use the ALTER TRIGGER statement, described in "ALTER TRIGGER Statement".