Adaptive Server imposes these limitations on triggers:
A table can have a maximum of three triggers: one update trigger, one insert trigger, and one delete trigger.
Each trigger can apply to only one table. However, a single trigger can incorporate all three user actions: update, insert, and delete.
You cannot create a trigger on a view or on a session-specific temporary table, though triggers can reference views or temporary tables.
The writetext statement does not activate insert or update triggers.
Although a truncate table statement is, similar to a delete without a where clause, because it removes all rows, it cannot fire a trigger, because individual row deletions are not logged.
You cannot create a trigger or build an index or a view on a temporary object (@object).
You cannot create triggers on system tables. If you try to create a trigger on a system table, Adaptive Server returns an error message and cancels the trigger.
You cannot use triggers that select from a text column or an image column in a table that has the same trigger inserts or deletes.
If Component Integration Services is enabled, triggers have limited usefulness on proxy tables because you cannot examine the rows being inserted, updated, or deleted (via the inserted and deleted tables). You can create, then invoke, a trigger on a proxy table. However, deleted or inserted data is not written to the transaction log for proxy tables because the insert is passed to the remote server. Therefore, the inserted and deleted tables, which are actually views to the transaction log, contain no data for proxy tables.
