Adaptive Server imposes the following 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 apply to all three user actions: update, insert, and delete.
You cannot create a trigger on a view or on a 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, in effect, like 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 of the inserted or deleted table.
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 a trigger on a proxy table, and it can be invoked. However, deleted or inserted data is not written to the transaction log for proxy tables because the insert is passed to the remote server. Hence, the inserted and deleted tables, which are actually views to the transaction log, contain no data for proxy tables.
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