CREATE TRIGGER acquires an exclusive table lock on the table.
The rows deleted or inserted are held in two temporary tables. In the Transact-SQL form of triggers, they can be accessed
using the table names "deleted", and "inserted", as in Adaptive Server Enterprise. In the Watcom SQL CREATE TRIGGER statement,
these rows are referenced using the REFERENCING clause.
Trigger names must be unique in the database.
Transact-SQL triggers are executed AFTER the triggering statement has executed.
Since the ORDER clause is not supported when creating Transact-SQL triggers, the value of trigger_order is set to 1. The SYSTRIGGER
system table has a unique index on: table_id, event, trigger_time, and trigger_order. For a particular event (insert, update,
delete), statement-level triggers are always AFTER and trigger_order cannot be set, so there can be only one of each type
per table, assuming any other triggers do not set an order other than 1. See Transact-SQL trigger overview.
ROW triggers are not supported by Adaptive Server Enterprise. SQL Anywhere's Transact-SQL dialect does not support Transact-SQL
INSTEAD OF triggers, though these are supported by Adaptive Server Enterprise.