SQL Server master----triggers from getting Started

-----Trigger-------------------        ---Trigger: is a special kind of stored procedure that is an action that occurs automatically when an operation is performedSelect *  fromQ_user--------------the Insert trigger--------------    if(object_id('Tr_insert','TR')) is  not NULL    Drop TriggerTr_insertCreate TriggerTr_insert onQ_user--a trigger based on which table is created (that is, which table is automatically triggered when an insert operation occurs)     for Insert --What happens when the action occurs automatically             --Action upate Insert Delete             --When a for is in operation occurs after an after operation, instead of the current operation, execution of the triggered action     as            --While inserting the Q_user, insert the UserInformation  --declare @uid varchar (@uName varchar)     --Select @uid =uid, @uName =uname from inserted     ----Get the corresponding row generated after the Operation     ----(insert represents triggered table-based)     --INSERT INTO userinformation (uid,name) VALUES (@uid, @uName)     ----You can also insert a SELECT statement     Insert  intoUserInformation (Uid,name)SelectUid,uname frominsertedGo    --Test    Insert  intoQ_user (UNAME,UPWD)Values('Trigger','11111')    Select *  fromuserinformation----Test success    ------The UPDATE trigger--------------Part of the field with new Q_user's colleague and new UserInformationCreate Triggertr_update onQ_user AfterUpdate     as      Declare @uid varchar( -),@name varchar( -)       Select @uid=Uid@name=UName fromInserted--get the corresponding row generated after the Operation      UpdateUserInformationSetName=@name whereUid=@uid            Go    UpdateQ_userSetUName='Update triggers' whereUName='Trigger'    Select *  fromuserinformation----delete Trigger---------because the UID inside the userinformation is the foreign key inside the Q_user, the error is not used when the cascade is deleted.DeleteQ_userwhereUid='10002' --The DELETE statement conflicts with the REFERENCE constraint "Df_uid". This conflict occurred in database "Qzone", table "Dbo.userinformation", column ' UID '         --Cascading is the ability to use cascading updates and deletes when a table and another table have a foreign key relationship .     --but only if this table is set to Cascade     --The Cascade method is set to create a Cascade update, and after the foreign key statement is added on the DELETE CASCADE on update NO CASCADE,                                                             --foreign KEY (userid) references UserInfo (userid) on DELETE Cascade             UpdateQ_userSetUName='cascading Updates' whereUName='Update triggers'      Select *  fromQ_user; Select *  fromuserinformation cascade deletion with triggers---Cursor---------        ---a way to process data that can be viewed or processed in a result set        --use cursors to query data for a specified interval (for example, query 10-40 for direct data containing 10-40)        Print(4.5)    

SQL Server master----triggers from getting Started