SQL SERVER – 2005 Understanding Trigger Recursion and Nesting with examples

Trigger events can be fired within another trigger action. One Trigger execution can trigger even on another table or same table. This trigger is called NESTED TRIGGER or RECURSIVE TRIGGER. Nested triggers SQL Server supports the nesting of triggers up to a maximum of 32 levels. Nesting means that when a trigger is fired, it will also cause another trigger to be fired. If a trigger creates an infinitive loop, the nesting level of 32 will be exceeded and the trigger will cancel with an error message. Recursive triggers When a trigger fires and performs a statement that will cause the same trigger to fire, recursion will occur. Below are examples of trigger recursion and nesting, plus how to turn them off.

Disable Nesting/Recursing Triggers
Following script will stop executing all the nested triggers.
sp_CONFIGURE 'nested_triggers',0
GO
RECONFIGURE
GO

There is also alternate way to stop Trigger Recursion

ALTER DATABASE databasename
SET RECURSIVE_TRIGGERS ON | OFF

Restrict Trigger Nesting to certain level
Put following script in trigger code. This will stop the trigger recursion after certain levels. In following case it will stop after 5 recursion.
IF ((
SELECT TRIGGER_NESTLEVEL()) > 5 )
RETURN


Published by Pinal Dave on SQLAuthority. More of my work at pinaldave.com.