What's the definition of direct recursive triggers and indirect recursive triggers

• mssqlnoob

  Ten Centuries

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  October 24, 2013 at 10:15 pm

  #278510

  Hi,

  my version is as follow:

  SELECT SERVERPROPERTY('productversion'), SERVERPROPERTY ('productlevel'), SERVERPROPERTY ('edition')

  (No column name)(No column name)(No column name)

  11.0.2100.60RTMExpress Edition (64-bit)

  Select @@version

  (No column name)

  Microsoft SQL Server 2012 - 11.0.2100.60 (X64)

  Feb 10 2012 19:39:15

  Copyright (c) Microsoft Corporation

  Express Edition (64-bit) on Windows NT 6.1 <X64> (Build 7601: Service Pack 1)

  FROM http://technet.microsoft.com/en-us/library/ms189799.aspx

  Indirect recursion

  With indirect recursion, an application updates table T1. This fires trigger TR1, updating table T2. In this scenario, trigger T2 then fires and updates table T1.

  Direct recursion

  With direct recursion, the application updates table T1. This fires trigger TR1, updating table T1. Because table T1 was updated, trigger TR1 fires again, and so on.

  http://technet.microsoft.com/en-us/library/ms190739.aspx

  Direct recursion

  This recursion occurs when a trigger fires and performs an action that causes the same trigger to fire again. For example, an application updates table T3; this causes trigger Trig3 to fire. Trig3 updates table T3 again; this causes trigger Trig3 to fire again.

  Direct recursion can also occur when the same trigger is called again, but after a trigger of a different type (AFTER or INSTEAD OF) is called.

  Indirect recursion

  This recursion occurs when a trigger fires and performs an action that causes another trigger of the same type (AFTER or INSTEAD OF) to fire.

  seems to me that both facts in http://technet.microsoft.com/en-us/library/ms190739.aspx are actually the same, i.e. they all gone through different tables, i.e indirect recursion. Is direct or indirect something to do with the intermediate tables or type of triggers in the intermediate stage.

  how do you classified the type of recursive trigger as stated in http://technet.microsoft.com/en-us/library/ms190739.aspx

  how do we know if a recursive trigger is direct or indirect?

  thanks