Final answer:
The ANSI SQL keywords used in SQL triggers are BEFORE, AFTER, and INSTEAD OF, which specify when the trigger should run relative to the database operation.
Step-by-step explanation:
The ANSI SQL keywords used in SQL triggers are BEFORE, AFTER, and INSTEAD OF. These keywords denote the timing of the trigger activation relative to the operation that it is associated with. A BEFORE trigger is executed before the operation (INSERT, UPDATE, DELETE) is performed on a table. An AFTER trigger runs after the operation has been completed. INSTEAD OF triggers are used for views to specify that they should execute in place of the usual operation.
For example, if you want to validate data before it is inserted into a table, you would use a BEFORE INSERT trigger. If you want to update a log table after data is updated in another table, an AFTER UPDATE trigger would be appropriate. If you need to perform complex operations on a view that normally does not support them, you would use an INSTEAD OF trigger.