15.00 - ALTER TRIGGER - Teradata Database

Teradata Database SQL Data Definition Language Detailed Topics

prodname
Teradata Database
vrm_release
15.00
category
Programming Reference
featnum
B035-1184-015K

ALTER TRIGGER

The Purpose of ALTER TRIGGER Options

The ALTER TRIGGER... DISABLED function is very useful in temporarily disabling or enabling triggers without dropping the triggers created for some purpose.

Utilities such as FastLoad and MultiLoad cannot operate on tables having enabled triggers defined on them. Disabling the triggers enables bulk loading of data into such tables.

The Teradata Parallel Data Pump utility operates even on tables with enabled triggers, but there can be some negative performance issues that arise if you do this.

Some triggers are created to coordinate actions on a set of tables. If such triggers are disabled for some period of time, the application must ensure that the relationship among the set of tables and the trigger is not lost.

The TIMESTAMP option is useful to change the order of execution of triggers, particularly those triggers that were created without the ORDER clause. If you do not specify a TIMESTAMP, then the existing timestamp for the trigger is not changed.

ALTER TRIGGER uses the current time when adding a timestamp, so when you want to change the timings for multiple order‑sensitive triggers defined on the same table, you must submit ALTER TRIGGER requests that change their timestamps in the required order to ensure the correct execution precedence.