Triggers firing other triggers   Suppose a trigger performs an action that would, if performed directly by a user, fire another trigger. SQL Anywhere and Adaptive Server Enterprise respond slightly differently to this situation. By default in Adaptive Server Enterprise, triggers fire other triggers up to a configurable nesting level, which has the default value of 16. You can control the nesting level with the Adaptive Server Enterprise nested triggers option. In SQL Anywhere, triggers fire other triggers without limit unless there is insufficient memory.

Triggers firing themselves   Suppose a trigger performs an action that would, if performed directly by a user, fire the same trigger. SQL Anywhere and Adaptive Server Enterprise respond slightly differently to this situation. By default, in SQL Anywhere, non-Transact-SQL triggers fire themselves recursively, whereas Transact-SQL dialect triggers do not fire themselves recursively. However, for Transact-SQL dialect triggers, you can use the self_recursion option of the SET statement [T-SQL] to allow a trigger to call itself recursively. See SET statement [T-SQL].

By default in Adaptive Server Enterprise, a trigger does not call itself recursively, but you can use the self_recursion option to allow recursion to occur.

ROLLBACK statement in triggers   Adaptive Server Enterprise permits the ROLLBACK TRANSACTION statement within triggers, to roll back the entire transaction of which the trigger is a part. SQL Anywhere does not permit ROLLBACK (or ROLLBACK TRANSACTION) statements in triggers because a triggering action and its trigger together form an atomic statement.

SQL Anywhere does provide the Adaptive Server Enterprise-compatible ROLLBACK TRIGGER statement to undo actions within triggers. See ROLLBACK TRIGGER statement.