I need to know about how the trigger execution happens for the below scenario.
I have 20 records in a table and I have an AFTER INSERT, UPDATE trigger on that table. When I'm updating all the records in that table using a MERGE or batch update statement, how will the trigger execute?
Does it execute for each row by row?
Or is it executing once per a batch (once for all 20 records)?
If it is execute once per batch do we need to write a loop inside the trigger to perform a task for each row?
Triggers in SQL Server always execute once per batch - there's no option for "for each row" triggers in SQL Server.
When you mass-update your table, the trigger will receive all the updated rows at once in the inserted and deleted pseudo tables and needs to deal with them accordingly - as a set of data - not a single row
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I'm planning to install a trigger on a table which is executed after every statement (foreach-statement).
But I'm not sure what statement exactly means. For example, if I do multiple inserts in one transaction, for example 1,000.
Will the trigger then be executed one time for a thousand times?
I want to make a stored procedure by which a Triggers will automatically execute after 5 seconds to check/show whether new row is updated or not.
I have a table called 'Inbox' in Database. I made a trigger for this whenever data in inserted in table.
CREATE TRIGGER tr_Inbox_ForInsert
ON Inbox
FOR INSERT
AS
BEGIN
SELECT * FROM inserted
END
I just want this trigger to execute itself after 5 seconds
That's not how triggers work... They are run after a transaction is carried out on the object they are attached to.
If you want something to run every X time interval, look into SQL Server Agent Jobs instead
I called update query from table1 trigger, when that query runs, it updates other table2 successfully but update trigger of table2 is fired only 1 time means not for every record that was updated from query of update
I'm using SQL Server 2008 Express edition-
Please guide me where I am wrong
Finally got the answer,
Trigger fire once for single query execution. mass or bulk update/insert/delete will not awake trigger for every row
The database I'm working on has a trigger which calls a stored procedure which takes 42 seconds to run if I do an UPDATE using T-SQL. If I edit the row in SQL Server Management Studio, the row updates instantly. Triggers are executed in the edit window as well as on T-SQL UPDATES, aren't they?
The SQL code in the stored procedure comes back instantly if I run it directly or call it using EXEC, the only circumstances when it runs slowly are when the trigger is called by an UPDATE statement.
It depends how the trigger was set up, Triggers will only run on Update, Delete and Insert statements (Depending which of the three are chosen) On the table it is set against.
Could you give the code used to create the trigger?
These triggers run after an insert, update or delete on a table
click here for details about different type of triggers and demo for triggers
I have a table that has an insert trigger on it. If I insert in 6000 records into this table in one insert statement from a stored procedure, will the stored procedure return before the insert trigger completes?
Just to make sure that I'm thinking correctly, the trigger should only be called (i know 'called' isn't the right word) once because there was only 1 insert statement, right?
My main question is: will the sproc finish even if the trigger hasn't completed?
Your insert trigger will run once for the entire insert statement. This is why it is important to use the inserted temporary table to see what has actually been inserted, and not just select the most recent single record, or something like that.
I just tested an insert and update trigger and indeed, they are considered part of the insert by sql server. the process will not finish until the trigger finishes.
Triggers are part of the transaction that called them.
One important thing about triggers that you must be aware of is that the trigger fires once for each transaction (at least in SQL server, you should check other dbs, but even if it will process row by row, that is usually a poor idea), so if you insert 6000 records the trigger fires once not 6000 times. Many people are not aware of this and write triggers as if they will process multiple record inserts one record at a time. This is not true and your trigger must account for handing the multiple record insert.
The trigger call is not asynchronous. Each call to your insert procedure will result in the trigger being fired, and the procedure will not return until the trigger finishes.
Take a look at the query plan to see how it works. You'll see that the statements in the trigger will be called for each call to the procedure.
The thing is, every time the TRIGGER criteria is met, the TRIGGER fires. It fires once in batch processing or Transaction. See my lesson 101 on TRIGGER
You should use cursor in insert statement to process trigger row.
Because Triggers in SQL Server fire once per statement, not once per row.