When the trigger event for the specified view is encountered,
the SQL statements of the trigger action are executed, instead of
the triggering statement. Triggers defined on a view support the following
syntax in the action clause.
This is not identical to the syntax of the trigger action for a
trigger on a table, as described in the section Triggered Action on a Table. Because no WHEN (condition)
is supported, the same trigger action is executed whenever the INSTEAD
OF trigger event is encountered, and only one action list can be specified,
rather than a separate list for each condition.