I wrote this trigger below. it is generating Error at:
Where UAssignment_Rights.user_id =i.user_id
from Inserted i
I want that when any row Deletes from Users table. It should also delete Deleted User Details from UAssignment_Rights Table.
Here in Image above Normalized Table is named as UAssignment_Rights
CREATE TRIGGER Trigger_Update ON Users
FOR DELETE
AS
set nocount on
DELETE
FROM UAssignment_Rights
Where UAssignment_Rights.user_id =i.user_id
from Inserted i
PRINT 'AFTER INSERT trigger fired.'
Can anyone answer my this question! Thank you.
Your syntax is wrong for deleting with a JOIN. Try this instead:
CREATE TRIGGER Trigger_Update ON Users
FOR DELETE
AS
SET NOCOUNT ON;
DELETE UR
FROM UAssignment_Rights UR
INNER JOIN Deleted D
ON UR.[user_id] = D.[user_id]
PRINT 'AFTER INSERT trigger fired.'
Also, this is for SQL Server (which seems to be the actual RDBMS that you are using, I don't know why you tagged this question with MySQL too)
Related
I am doing an after insert trigger on a table where I delete the rows that are incorrect, however, I am unable to do this and I can't find the correct syntax anywhere.
From what I understand, the table where the rows will be deleted from is in the FROM clause but I also need to use the inserted table. How do I do this?
I know this can be solved using an instead of insert trigger but I really want to know how to do this way.
DELETE
FROM promotion p, inserted i
WHERE <conditions>
You can try like this:
CREATE TRIGGER myTrigger ON dbo.MyTable
FOR INSERT
AS
SET NOCOUNT ON;
DELETE sometarget
FROM dbo.MyTable AS sometarget
JOIN inserted ON inserted.ID = sometarget.ID
WHERE <conditions>;
GO
I created a trigger in SQL Server 2005 that inserts records into a history table whenever a deletion occurs in the source table. The records are getting inserted, but they are not getting deleted from the source table.
Here is my trigger:
CREATE TRIGGER TRG_EdiHistory
ON dbo.EDI10000
INSTEAD OF DELETE
AS
BEGIN
SET NOCOUNT ON;
SET IDENTITY_INSERT dbo.EDI10500 ON;
INSERT INTO EDI10500(File_Id, Tp_Id, File_Name, File_Size, File_Data, Rec_Date, Content_Type, Update_Flag)
SELECT
File_Id, Tp_Id, File_Name, File_Size, File_Data,
Rec_Date, Content_Type, Update_Flag
FROM
DELETED
END
GO
I had to use an INSTEAD OF trigger because my tables contains Image type columns.
Please if anyone has any idea why this is happening.
Thank you.
* UPDATE *
CREATE TRIGGER TRG_EdiHistory
ON dbo.EDI10000
INSTEAD OF DELETE
AS
BEGIN
SET NOCOUNT ON;
SET IDENTITY_INSERT dbo.EDI10500 ON;
INSERT INTO EDI10500 ([File_Id],Tp_Id,[File_Name],File_Size
,File_Data,Rec_Date,Content_Type,Update_Flag)
SELECT [File_Id], Tp_Id, [File_Name], File_Size, File_Data,
Rec_Date, Content_Type, Update_Flag
FROM DELETED
DELETE FROM dbo.EDI10000
WHERE EXISTS (SELECT 1
FROM DELETED
WHERE [FILE_ID] = dbo.EDI10000.[File_Id])
END
GO
Instead of Triggers , fire Instead of the triggering action. In your Case this instead of Trigger fires and Inserts data into your history table.
Note this trigger fires instead of the Delete command. So if you also want to Delete rows you will need to add Delete statement inside this trigger.
Having said this I think instead of Instead Trigger if you simply define an After Trigger with same definition as your this instead of trigger will makes things pretty simple. It will delete the rows from table and then insert rows into your history table as you are expecting it to work.
Update
Since you have mentioned you cannot use Image Data type inside an After Trigger in sql server 2005, I am not aware of this limitation. Well in this case you can simply add a delete statement inside your this existing instead of trigger.
DELETE FROM dbo.table
WHERE EXISTS (SELECT 1
FROM deleted
WHERE Pk_Column = table.PK_Column)
Instead of delete replaces the standard action of the DELETE statement.
http://technet.microsoft.com/en-us/library/ms191208(v=sql.105).aspx
Have a look here how to do what you really want:
How to create a before delete trigger in SQL Server?
I have found a trigger example for Creation and Modification of the record but the question is, should I create those two triggers for each table or is there any way to run them on each update and insert regardless of the table name. Of course the names of the fields will be unique for each table for instance "CreationDate", "LastUpdate". Actually first question should have been, is creating a trigger for such a case a correct practice or should I handle it on code behind?
Here is the trigger that I have found on the internet;
CREATE TRIGGER tr[TableName]CreateDate ON [TableName]
FOR INSERT
AS
UPDATE [TableName] SET [TableName].Created=getdate()
FROM [TableName] INNER JOIN Inserted ON [TableName].[UniqueID]= Inserted.[UniqueID]
GO
CREATE TRIGGER tr[TableName]LastModifiedDate ON [TableName]
FOR UPDATE
AS
UPDATE [TableName] SET [TableName].LastModified=getdate()
FROM [TableName] INNER JOIN Inserted ON [TableName].[UniqueID]= Inserted.[UniqueID]
Triggers can be created on DML (Tables, Views events) or DDL (Create, Alter, Drop etc). You can not create a generic trigger which applies to all tables, you need to specify the table name.
You could create a script which automates the Trigger scripts creation for all tables if need be.
More info on: http://msdn.microsoft.com/en-us/library/ms189799.aspx
Just give your trigger the option to run for INSERT AND UPDATE
CREATE TRIGGER [dbo].[tr_TableName] ON [dbo].[TableName] FOR INSERT,DELETE,UPDATE AS
BEGIN
/*
Do stuff here.
*/
Select * from Inserted
Select * from deleted
END
I want to copy the contents of a column into another column in the same table. Therefore, I created this trigger:
ALTER TRIGGER [dbo].[kennscht_copy_to_prodverpt]
ON [dbo].[Stammdaten]
AFTER INSERT
AS
UPDATE Stammdaten
SET PRODVERPT = (SELECT KENNSCHT FROM INSERTED)
WHERE SNR = (SELECT SNR FROM INSERTED);
But when I use an UPDATE on the table to update KENNSCHT to a different value, PRODVERPT is not updated as well. Now, you could argue that is because the trigger is on AFTER INSERT and not AFTER UPDATE, but when I change it so it's triggered by UPDATE and INSERT, whenever I update any row, I get an error message from SQL Server
Cannot update row because it would make the row not unique or update multiple rows (2 rows) [sic]
What is going on here? Either the trigger doesn't do anything, or it's messing up the whole table, making it un-updateable.
Update: I also tried the following trigger:
UPDATE s
SET s.PRODVERPT = i.KENNSCHT
FROM Stammdaten s
INNER JOIN INSERTED i ON i.SNR = s.SNR;
But it has exactly the same behaviour. If I use only AFTER INSERT, nothing changes and if I use AFTER INSERT, UPDATE I get the error message above.
Update 2: There are no multiple rows in the table, I already checked that because I thought it might be connected to the issue.
If you run this trigger as an AFTER UPDATE trigger, it runs recursively, since it always issues another UPDATE statement against the same table, which leads to another execution of the trigger.
To work around this, you either need to make the update trigger an INSTEAD OF UPDATE trigger or test if the KENNSCHT column was modified at all. For the latter you can use the UPDATE() function like this:
ALTER TRIGGER [dbo].[kennscht_copy_to_prodverpt_after_update]
ON [dbo].[Stammdaten]
AFTER UPDATE
AS
BEGIN
SET NOCOUNT ON
IF (UPDATE(KENNSCHT))
BEGIN
UPDATE s
SET s.PRODVERPT = i.KENNSCHT
FROM Stammdaten s
INNER JOIN INSERTED i ON i.SNR = s.SNR
END
END
I'm using Sqlserver express and I can't do before updated trigger. There's a other way to do that?
MSSQL does not support BEFORE triggers. The closest you have is INSTEAD OF triggers but their behavior is different to that of BEFORE triggers in MySQL.
You can learn more about them here, and note that INSTEAD OF triggers "Specifies that the trigger is executed instead of the triggering SQL statement, thus overriding the actions of the triggering statements." Thus, actions on the update may not take place if the trigger is not properly written/handled. Cascading actions are also affected.
You may instead want to use a different approach to what you are trying to achieve.
It is true that there aren't "before triggers" in MSSQL. However, you could still track the changes that were made on the table, by using the "inserted" and "deleted" tables together. When an update causes the trigger to fire, the "inserted" table stores the new values and the "deleted" table stores the old values. Once having this info, you could relatively easy simulate the "before trigger" behaviour.
Can't be sure if this applied to SQL Server Express, but you can still access the "before" data even if your trigger is happening AFTER the update. You need to read the data from either the deleted or inserted table that is created on the fly when the table is changed. This is essentially what #Stamen says, but I still needed to explore further to understand that (helpful!) answer.
The deleted table stores copies of the affected rows during DELETE and
UPDATE statements. During the execution of a DELETE or UPDATE
statement, rows are deleted from the trigger table and transferred to
the deleted table...
The inserted table stores copies of the affected rows during INSERT
and UPDATE statements. During an insert or update transaction, new
rows are added to both the inserted table and the trigger table...
https://msdn.microsoft.com/en-us/library/ms191300.aspx
So you can create your trigger to read data from one of those tables, e.g.
CREATE TRIGGER <TriggerName> ON <TableName>
AFTER UPDATE
AS
BEGIN
INSERT INTO <HistoryTable> ( <columns...>, DateChanged )
SELECT <columns...>, getdate()
FROM deleted;
END;
My example is based on the one here:
http://www.seemoredata.com/en/showthread.php?134-Example-of-BEFORE-UPDATE-trigger-in-Sql-Server-good-for-Type-2-dimension-table-updates
sql-server triggers
T-SQL supports only AFTER and INSTEAD OF triggers, it does not feature a BEFORE trigger, as found in some other RDBMSs.
I believe you will want to use an INSTEAD OF trigger.
All "normal" triggers in SQL Server are "AFTER ..." triggers. There are no "BEFORE ..." triggers.
To do something before an update, check out INSTEAD OF UPDATE Triggers.
To do a BEFORE UPDATE in SQL Server I use a trick. I do a false update of the record (UPDATE Table SET Field = Field), in such way I get the previous image of the record.
Remember that when you use an instead trigger, it will not commit the insert unless you specifically tell it to in the trigger. Instead of really means do this instead of what you normally do, so none of the normal insert actions would happen.
Full example:
CREATE TRIGGER [dbo].[trig_020_Original_010_010_Gamechanger]
ON [dbo].[T_Original]
AFTER UPDATE
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
DECLARE #Old_Gamechanger int;
DECLARE #New_Gamechanger int;
-- Insert statements for trigger here
SELECT #Old_Gamechanger = Gamechanger from DELETED;
SELECT #New_Gamechanger = Gamechanger from INSERTED;
IF #Old_Gamechanger != #New_Gamechanger
BEGIN
INSERT INTO [dbo].T_History(ChangeDate, Reason, Callcenter_ID, Old_Gamechanger, New_Gamechanger)
SELECT GETDATE(), 'Time for a change', Callcenter_ID, #Old_Gamechanger, #New_Gamechanger
FROM deleted
;
END
END
The updated or deleted values are stored in DELETED. we can get it by the below method in trigger
Full example,
CREATE TRIGGER PRODUCT_UPDATE ON PRODUCTS
FOR UPDATE
AS
BEGIN
DECLARE #PRODUCT_NAME_OLD VARCHAR(100)
DECLARE #PRODUCT_NAME_NEW VARCHAR(100)
SELECT #PRODUCT_NAME_OLD = product_name from DELETED
SELECT #PRODUCT_NAME_NEW = product_name from INSERTED
END