With 'For Insert' trigger, are rows inserted to the table yet when it is triggered?
CREATE Trigger check_availability on Room
For Insert, Update
Thanks!
Yes.
CREATE TRIGGER
FOR | AFTER
AFTER specifies that the DML trigger is fired only when all operations specified in the triggering SQL statement have executed successfully. All referential cascade actions and constraint checks also must succeed before this trigger fires.
AFTER is the default when FOR is the only keyword specified.
AFTER triggers cannot be defined on views.
Related
I have 2 triggers (Insert and Update)
CREATE TRIGGER my_InsertTrigger
AFTER INSERT ON `table`
FOR EACH ROW
BEGIN
Update a previous record if found
END //
CREATE TRIGGER my_UpdateTrigger
AFTER UPDATE ON `table`
FOR EACH ROW
BEGIN
.....
END //
According to my understanding triggers cannot be fire programmatically/manually, it only fires when an insert/update/delete happens on that table.
So my question is in the case mentioned above, will the insert trigger(my_InsertTrigger) invoke the update trigger (my_UpdateTrigger)?
Thanks in advance.
When I changed the trigger syntax to SQL Server (with just inserting one row) one trigger that causes an update on a table will kick off the update trigger on that table (if it exists).
I have seen this on audit tables and two things can, and will, happen:
1) Performance will suffer.
2) If the audit triggers start kicking each other off (by having cross trggers) you can run out of stack space (The triggers can nest 32 levels down).
I was going through the different type of Triggers from here
This article is sayiong triggers are classified into two main types:-
After Triggers // This fires after row is inserted/updated/deleted
Instead Of Triggers // This fires before the row is inserted/updated/deleted
In which category does the following trigger fit?
create trigger TriggerName
on TableName For Insert
As
From here:
AFTER is the default when FOR is the only keyword specified.
I have a trigger on update of a table that inserts into another table. This other table only exists in one location (the table is not replicated). If I set the trigger as not for replication, will my update trigger still fire when replicated data comes in to the table with the trigger? That way I can have the trigger and the tables that it inserts into in only one location.
No: this is the point of NOT FOR REPLICATION. From MSDN
Triggers
The trigger is not executed when a replication agent performs an insert, update, or delete operation.
The key here is "replication agent": this is the process that makes the trigger not fire
I need to delete a trigger in SQL Server. Seems like it should be simple enough, but because there is a thing called a "delete trigger", a trigger that is invoked upon deletion, it seems impossible to find resources on how to actually delete an already existing trigger.
DROP TRIGGER:
Removes one or more triggers from the current database...
You can remove a trigger by dropping it or by dropping the trigger table. When a table is dropped, all associated triggers are also dropped. When a trigger is dropped, information about the trigger is removed from the sysobjects and syscomments system tables.
Use DROP TRIGGER and CREATE TRIGGER to rename a trigger. Use ALTER TRIGGER to change the definition of a trigger...
To drop a trigger, this works:
DROP TRIGGER [trigger_name];
If you want to check weather trigger exist before a drop, then use:
SELECT * FROM [sys].[triggers] WHERE [name] = 'MyTrigger'
For more check out http://www.tsql.info/triggers/drop-trigger.php and https://stackoverflow.com/a/636470/2218697
I can Drop a Trigger with the Following Query
DROP TRIGGER [Trigger_Name]
(OR)
DROP TRIGGER Trigger_Update
Hope this Must helpfull...
For SQL Server 2016 and above
DROP TRIGGER IF EXISTS [dbo].[trg]
https://learn.microsoft.com/en-us/sql/t-sql/statements/drop-trigger-transact-sql
DROP TRIGGER IF EXISTS [dbo].[trigger_name];
I have two triggers on one of the tables in my database. One is for insert trigger and the other is an after update trigger. The insert trigger will update the table with values. My question is this; Is it possible that that the update trigger is firing at the same time that the insert is doing its job?
A FOR INSERT trigger will fire only on INSERT statements. A FOR UPDATE trigger will fire only on UPDATE statements. Of course, if your insert trigger executes any UPDATE statements then it will fire the update trigger, and vice versa.
Your UPDATE trigger won't fire for an INSERT statement (excepting the update-within-trigger case above), but of course you still have to design for concurrency, since it's possible for two different users to be running two different operations at the same time - one INSERT and one UPDATE.
If your insert trigger does an update to the table, the update trigger will be called. If a trigger triggers another trigger, it's called a "recursive trigger".
Recursive triggers can be disabled for an entire server:
sp_configure 'nested_triggers', 0
go
reconfigure
Or for one database:
alter database yourdb set recursive_triggers off