Most Teradata load utilities cannot access a table that has an active trigger.
An application that uses triggers can use ALTER TRIGGER to disable the trigger and enable the load. The application must be sure that loading a table with disabled triggers does not result in a mismatch in a user defined relationship with a table referenced in the triggered action.
Other restrictions on triggers include:
- BEFORE statement triggers are not allowed.
- BEFORE triggers cannot have data-changing statements as triggered action (triggered SQL statements).
- BEFORE triggers cannot access OLD TABLE, NEW TABLE, or OLD_NEW_TABLE.
- Triggers and hash indexes are mutually exclusive. You cannot define triggers on a table on which a hash index is already defined.
- A positioned (updatable cursor) UPDATE or DELETE is not allowed to fire a trigger. An attempt to do so generates an error.
- You cannot define triggers on an error logging table.