Sybase DC38133-01-0902-01 manual Body of your triggers, Actions carried out by conflict

Chapter 6. Principles of SQL Remote Design

	The Adaptive Server Anywhere FIRE_TRIGGERS database option prevents
	triggers from being fired. If you set this option for the user ID used by the
	Message Agent, be careful to not use this user ID for other purposes.
	An alternative approach to preventing trigger execution, available only for
	Adaptive Server Anywhere, is to use the following condition around the
	body of your triggers:
	IF CURRENT REMOTE USER IS NULL
	This make execution conditional on whether the current user is the Message
	Agent.
Trigger replication from	By default, the Message Agent for Adaptive Server Anywhere does not
Adaptive Server	replicate actions performed by triggers; it is assumed that the trigger is
Anywhere	defined remotely. This avoids permissions issues and the possibility of each
	action occurring twice. There are some exceptions to this rule:
	♦ Conflict resolution trigger actions	The actions carried out by conflict
	resolution, or RESOLVE UPDATE, triggers are replicated from a
	consolidated database to all remote databases, including the one that sent
	the message causing the conflict.
	♦ Replication of BEFORE triggers	Some BEFORE triggers can produce
	undesirable results when using SQL Remote, and so BEFORE trigger
	actions that modify the row being updated are replicated, before
	UPDATE actions.
	You must be aware of this behavior when designing your installation. For
	example, a BEFORE UPDATE that bumps a counter column in the row
	to keep track of the number of times a row is updated would double count
	if replicated, as the BEFORE UPDATE trigger will fire when the
	UPDATE is replicated. To prevent this problem, you must ensure that, at
	the subscriber database, the trigger is not present or does not carry out the
	replicated action. Also, a BEFORE UPDATE that sets a column to the
	time of the last update will get the time the UPDATE is replicated as well.
An option to replicate	The Adaptive Server Anywhere Message Agent has an option that causes it
trigger actions	to replicate all trigger actions when sending messages. This is the dbremote
	-toption.

If you use this option, you must ensure that the trigger actions are not carried out twice at remote databases, once by the trigger being fired at the remote site, and once by the explicit application of the replicated actions from the consolidated database.

To ensure that trigger actions are not carried out twice, you can wrap an IF

CURRENT REMOTE USER IS NULL . . . END IF statement around the

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