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sholana
Starting Member
4 Posts |
 Posted - 2002-06-18 : 11:09:34
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| I am trying to write a trigger to test if the entered value is in another table and rollback if not.... so far I have this...But the select statement is no right help!!!CREATE TRIGGER Advertisement_Table_insert ON AdvertisementFOR INSERT, UPDATE ASIF Update( Author_id) Begin IF Not (Author_id is NULL) BEGIN IF NOT EXISTS(SELECT User_id FROM USERS WHERE User_id = Author_id) <<<<< BEGIN Raiserror('Author_id not in Users Table', 16, 1) ROLLBACK TRANSACTION END END END |
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setbasedisthetruepath
Used SQL Salesman
992 Posts |
Posted - 2002-06-18 : 11:17:53
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quote:
But the select statement is no right help!!!
It's not the select statement that is incorrect; your "IF Not (Author_id is NULL)" is incorrect. A trigger fires on the statement, regardless of the # of rows affected. Your trigger will fire on updates of 0, 1, or more than 1 row(s), so you need to qualify which row you are talking about when you check if the author_id column is null.You might also consider creating a foreign key relationship between users.user_id and advertisement.author_id.setBasedIsTheTruepath<O>Edited by - setbasedisthetruepath on 06/18/2002 11:18:13 |
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Triggers