Insert Update trigger how to determine if insert or update - sql-server

I need to write an Insert, Update Trigger on table A which will delete all rows from table B whose one column (say Desc) has values like the value inserted/updated in the table A's column (say Col1). How would I go around writing it so that I can handle both Update and Insert cases. How would I determine if the trigger is executed for an update or insert.

Triggers have special INSERTED and DELETED tables to track "before" and "after" data. So you can use something like IF EXISTS (SELECT * FROM DELETED) to detect an update. You only have rows in DELETED on update, but there are always rows in INSERTED.
Look for "inserted" in CREATE TRIGGER.
Edit, 23 Nov 2011
After comment, this answer is only for INSERTED and UPDATED triggers.
Obviously, DELETE triggers can not have "always rows in INSERTED" as I said above

CREATE TRIGGER dbo.TableName_IUD
ON dbo.TableName
AFTER INSERT, UPDATE, DELETE
AS
BEGIN
SET NOCOUNT ON;
--
-- Check if this is an INSERT, UPDATE or DELETE Action.
--
DECLARE #action as char(1);
SET #action = 'I'; -- Set Action to Insert by default.
IF EXISTS(SELECT * FROM DELETED)
BEGIN
SET #action =
CASE
WHEN EXISTS(SELECT * FROM INSERTED) THEN 'U' -- Set Action to Updated.
ELSE 'D' -- Set Action to Deleted.
END
END
ELSE
IF NOT EXISTS(SELECT * FROM INSERTED) RETURN; -- Nothing updated or inserted.
...
END

Many of these suggestions do not take into account if you run a delete statement that deletes nothing.
Say you try to delete where an ID equals some value that does not exist in the table.
Your trigger still gets called but there is nothing in the Deleted or Inserted tables.
Use this to be safe:
--Determine if this is an INSERT,UPDATE, or DELETE Action or a "failed delete".
DECLARE #Action as char(1);
SET #Action = (CASE WHEN EXISTS(SELECT * FROM INSERTED)
AND EXISTS(SELECT * FROM DELETED)
THEN 'U' -- Set Action to Updated.
WHEN EXISTS(SELECT * FROM INSERTED)
THEN 'I' -- Set Action to Insert.
WHEN EXISTS(SELECT * FROM DELETED)
THEN 'D' -- Set Action to Deleted.
ELSE NULL -- Skip. It may have been a "failed delete".
END)
Special thanks to #KenDog and #Net_Prog for their answers.
I built this from their scripts.

I'm using the following, it also correctly detect delete statements that delete nothing:
CREATE TRIGGER dbo.TR_TableName_TriggerName
ON dbo.TableName
AFTER INSERT, UPDATE, DELETE
AS
BEGIN
SET NOCOUNT ON;
IF NOT EXISTS(SELECT * FROM INSERTED)
-- DELETE
PRINT 'DELETE';
ELSE
BEGIN
IF NOT EXISTS(SELECT * FROM DELETED)
-- INSERT
PRINT 'INSERT';
ELSE
-- UPDATE
PRINT 'UPDATE';
END
END;

Declare #Type varchar(50)='';
IF EXISTS (SELECT * FROM inserted) and EXISTS (SELECT * FROM deleted)
BEGIN
SELECT #Type = 'UPDATE'
END
ELSE IF EXISTS(SELECT * FROM inserted)
BEGIN
SELECT #Type = 'INSERT'
END
ElSE IF EXISTS(SELECT * FROM deleted)
BEGIN
SELECT #Type = 'DELETE'
END

I believe nested ifs a little confusing and:
Flat is better than nested [The Zen of Python]
;)
DROP TRIGGER IF EXISTS AFTER_MYTABLE
GO
CREATE TRIGGER dbo.AFTER_MYTABLE ON dbo.MYTABLE AFTER INSERT, UPDATE, DELETE
AS BEGIN
--- FILL THE BEGIN/END SECTION FOR YOUR NEEDS.
SET NOCOUNT ON;
IF EXISTS(SELECT * FROM INSERTED) AND EXISTS(SELECT * FROM DELETED)
BEGIN PRINT 'UPDATE' END
ELSE IF EXISTS(SELECT * FROM INSERTED) AND NOT EXISTS(SELECT * FROM DELETED)
BEGIN PRINT 'INSERT' END
ELSE IF EXISTS(SELECT * FROM DELETED) AND NOT EXISTS(SELECT * FROM INSERTED)
BEGIN PRINT 'DELETED' END
ELSE BEGIN PRINT 'NOTHING CHANGED'; RETURN; END -- NOTHING
END

After a lot of searching I could not find an exact example of a single SQL Server trigger that handles all (3) three conditions of the trigger actions INSERT, UPDATE, and DELETE. I finally found a line of text that talked about the fact that when a DELETE or UPDATE occurs, the common DELETED table will contain a record for these two actions. Based upon that information, I then created a small Action routine which determines why the trigger has been activated. This type of interface is sometimes needed when there is both a common configuration and a specific action to occur on an INSERT vs. UPDATE trigger. In these cases, to create a separate trigger for the UPDATE and the INSERT would become maintenance problem. (i.e. were both triggers updated properly for the necessary common data algorithm fix?)
To that end, I would like to give the following multi-trigger event code snippet for handling INSERT, UPDATE, DELETE in one trigger for an Microsoft SQL Server.
CREATE TRIGGER [dbo].[INSUPDDEL_MyDataTable]
ON [dbo].[MyDataTable] FOR INSERT, UPDATE, DELETE
AS
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with caller queries SELECT statements.
-- If an update/insert/delete occurs on the main table, the number of records affected
-- should only be based on that table and not what records the triggers may/may not
-- select.
SET NOCOUNT ON;
--
-- Variables Needed for this Trigger
--
DECLARE #PACKLIST_ID varchar(15)
DECLARE #LINE_NO smallint
DECLARE #SHIPPED_QTY decimal(14,4)
DECLARE #CUST_ORDER_ID varchar(15)
--
-- Determine if this is an INSERT,UPDATE, or DELETE Action
--
DECLARE #Action as char(1)
DECLARE #Count as int
SET #Action = 'I' -- Set Action to 'I'nsert by default.
SELECT #Count = COUNT(*) FROM DELETED
if #Count > 0
BEGIN
SET #Action = 'D' -- Set Action to 'D'eleted.
SELECT #Count = COUNT(*) FROM INSERTED
IF #Count > 0
SET #Action = 'U' -- Set Action to 'U'pdated.
END
if #Action = 'D'
-- This is a DELETE Record Action
--
BEGIN
SELECT #PACKLIST_ID =[PACKLIST_ID]
,#LINE_NO = [LINE_NO]
FROM DELETED
DELETE [dbo].[MyDataTable]
WHERE [PACKLIST_ID]=#PACKLIST_ID AND [LINE_NO]=#LINE_NO
END
Else
BEGIN
--
-- Table INSERTED is common to both the INSERT, UPDATE trigger
--
SELECT #PACKLIST_ID =[PACKLIST_ID]
,#LINE_NO = [LINE_NO]
,#SHIPPED_QTY =[SHIPPED_QTY]
,#CUST_ORDER_ID = [CUST_ORDER_ID]
FROM INSERTED
if #Action = 'I'
-- This is an Insert Record Action
--
BEGIN
INSERT INTO [MyChildTable]
(([PACKLIST_ID]
,[LINE_NO]
,[STATUS]
VALUES
(#PACKLIST_ID
,#LINE_NO
,'New Record'
)
END
else
-- This is an Update Record Action
--
BEGIN
UPDATE [MyChildTable]
SET [PACKLIST_ID] = #PACKLIST_ID
,[LINE_NO] = #LINE_NO
,[STATUS]='Update Record'
WHERE [PACKLIST_ID]=#PACKLIST_ID AND [LINE_NO]=#LINE_NO
END
END

while i do also like the answer posted by #Alex, i offer this variation to #Graham's solution above
this exclusively uses record existence in the INSERTED and UPDATED tables, as opposed to using COLUMNS_UPDATED for the first test.
It also provides the paranoid programmer relief knowing that the final case has been considered...
declare #action varchar(4)
IF EXISTS (SELECT * FROM INSERTED)
BEGIN
IF EXISTS (SELECT * FROM DELETED)
SET #action = 'U' -- update
ELSE
SET #action = 'I' --insert
END
ELSE IF EXISTS (SELECT * FROM DELETED)
SET #action = 'D' -- delete
else
set #action = 'noop' --no records affected
--print #action
you will get NOOP with a statement like the following :
update tbl1 set col1='cat' where 1=2

DECLARE #ActionType CHAR(6);
SELECT #ActionType = COALESCE(CASE WHEN EXISTS(SELECT * FROM INSERTED)
AND EXISTS(SELECT * FROM DELETED) THEN 'UPDATE' END,
CASE WHEN EXISTS(SELECT * FROM DELETED) THEN 'DELETE' END,
CASE WHEN EXISTS(SELECT * FROM INSERTED) THEN 'INSERT' END);
PRINT #ActionType;

Try this..
ALTER TRIGGER ImportacionesGS ON dbo.Compra
AFTER INSERT, UPDATE, DELETE
AS
BEGIN
-- idCompra is PK
DECLARE #vIdCompra_Ins INT,#vIdCompra_Del INT
SELECT #vIdCompra_Ins=Inserted.idCompra FROM Inserted
SELECT #vIdCompra_Del=Deleted.idCompra FROM Deleted
IF (#vIdCompra_Ins IS NOT NULL AND #vIdCompra_Del IS NULL)
Begin
-- Todo Insert
End
IF (#vIdCompra_Ins IS NOT NULL AND #vIdCompra_Del IS NOT NULL)
Begin
-- Todo Update
End
IF (#vIdCompra_Ins IS NULL AND #vIdCompra_Del IS NOT NULL)
Begin
-- Todo Delete
End
END

This might be a faster way:
DECLARE #action char(1)
IF COLUMNS_UPDATED() > 0 -- insert or update
BEGIN
IF EXISTS (SELECT * FROM DELETED) -- update
SET #action = 'U'
ELSE
SET #action = 'I'
END
ELSE -- delete
SET #action = 'D'

I found a small error in Grahams otherwise cool solution:
It should be
IF COLUMNS_UPDATED() <> 0 -- insert or update
instead of > 0
probably because top bit gets interpreted as SIGNED integer sign bit...(?).
So in total:
DECLARE #action CHAR(8)
IF COLUMNS_UPDATED() <> 0 -- delete or update?
BEGIN
IF EXISTS (SELECT * FROM deleted) -- updated cols + old rows means action=update
SET #action = 'UPDATE'
ELSE
SET #action = 'INSERT' -- updated columns and nothing deleted means action=insert
END
ELSE -- delete
BEGIN
SET #action = 'DELETE'
END

A potential problem with the two solutions offered is that, depending on how they are written, an update query may update zero records and an insert query may insert zero records. In these cases, the Inserted and Deleted recordsets will be empty. In many cases, if both the Inserted and Deleted recordsets are empty you might just want to exit the trigger without doing anything.

declare #insCount int
declare #delCount int
declare #action char(1)
select #insCount = count(*) from INSERTED
select #delCount = count(*) from DELETED
if(#insCount > 0 or #delCount > 0)--if something was actually affected, otherwise do nothing
Begin
if(#insCount = #delCount)
set #action = 'U'--is update
else if(#insCount > 0)
set #action = 'I' --is insert
else
set #action = 'D' --is delete
--do stuff here
End

This does the trick for me:
declare #action_type int;
select #action_type = case
when i.id is not null and d.id is null then 1 -- insert
when i.id is not null and d.id is not null then 2 -- update
when i.id is null and d.id is not null then 3 -- delete
end
from inserted i
full join deleted d on d.id = i.id
Since not all columns can be updated at a time you can check whether a particular column is being updated by something like this:
IF UPDATE([column_name])

just simple way
CREATE TRIGGER [dbo].[WO_EXECUTION_TRIU_RECORD] ON [dbo].[WO_EXECUTION]
WITH EXECUTE AS CALLER
FOR INSERT, UPDATE
AS
BEGIN
select #vars = [column] from inserted
IF UPDATE([column]) BEGIN
-- do update action base on #vars
END ELSE BEGIN
-- do insert action base on #vars
END
END

I like solutions that are "computer science elegant." My solution here hits the [inserted] and [deleted] pseudotables once each to get their statuses and puts the result in a bit mapped variable. Then each possible combination of INSERT, UPDATE and DELETE can readily be tested throughout the trigger with efficient binary evaluations (except for the unlikely INSERT or DELETE combination).
It does make the assumption that it does not matter what the DML statement was if no rows were modified (which should satisfy the vast majority of cases). So while it is not as complete as Roman Pekar's solution, it is more efficient.
With this approach, we have the possibility of one "FOR INSERT, UPDATE, DELETE" trigger per table, giving us A) complete control over action order and b) one code implementation per multi-action-applicable action. (Obviously, every implementation model has its pros and cons; you will need to evaluate your systems individually for what really works best.)
Note that the "exists (select * from «inserted/deleted»)" statements are very efficient since there is no disk access (https://social.msdn.microsoft.com/Forums/en-US/01744422-23fe-42f6-9ab0-a255cdf2904a).
use tempdb
;
create table dbo.TrigAction (asdf int)
;
GO
create trigger dbo.TrigActionTrig
on dbo.TrigAction
for INSERT, UPDATE, DELETE
as
declare #Action tinyint
;
-- Create bit map in #Action using bitwise OR "|"
set #Action = (-- 1: INSERT, 2: DELETE, 3: UPDATE, 0: No Rows Modified
(select case when exists (select * from inserted) then 1 else 0 end)
| (select case when exists (select * from deleted ) then 2 else 0 end))
;
-- 21 <- Binary bit values
-- 00 -> No Rows Modified
-- 01 -> INSERT -- INSERT and UPDATE have the 1 bit set
-- 11 -> UPDATE <
-- 10 -> DELETE -- DELETE and UPDATE have the 2 bit set
raiserror(N'#Action = %d', 10, 1, #Action) with nowait
;
if (#Action = 0) raiserror(N'No Data Modified.', 10, 1) with nowait
;
-- do things for INSERT only
if (#Action = 1) raiserror(N'Only for INSERT.', 10, 1) with nowait
;
-- do things for UPDATE only
if (#Action = 3) raiserror(N'Only for UPDATE.', 10, 1) with nowait
;
-- do things for DELETE only
if (#Action = 2) raiserror(N'Only for DELETE.', 10, 1) with nowait
;
-- do things for INSERT or UPDATE
if (#Action & 1 = 1) raiserror(N'For INSERT or UPDATE.', 10, 1) with nowait
;
-- do things for UPDATE or DELETE
if (#Action & 2 = 2) raiserror(N'For UPDATE or DELETE.', 10, 1) with nowait
;
-- do things for INSERT or DELETE (unlikely)
if (#Action in (1,2)) raiserror(N'For INSERT or DELETE.', 10, 1) with nowait
-- if already "return" on #Action = 0, then use #Action < 3 for INSERT or DELETE
;
GO
set nocount on;
raiserror(N'
INSERT 0...', 10, 1) with nowait;
insert dbo.TrigAction (asdf) select top 0 object_id from sys.objects;
raiserror(N'
INSERT 3...', 10, 1) with nowait;
insert dbo.TrigAction (asdf) select top 3 object_id from sys.objects;
raiserror(N'
UPDATE 0...', 10, 1) with nowait;
update t set asdf = asdf /1 from dbo.TrigAction t where asdf <> asdf;
raiserror(N'
UPDATE 3...', 10, 1) with nowait;
update t set asdf = asdf /1 from dbo.TrigAction t;
raiserror(N'
DELETE 0...', 10, 1) with nowait;
delete t from dbo.TrigAction t where asdf < 0;
raiserror(N'
DELETE 3...', 10, 1) with nowait;
delete t from dbo.TrigAction t;
GO
drop table dbo.TrigAction
;
GO

Quick solution MySQL
By the way: I'm using MySQL PDO.
(1) In an auto increment table just get the highest value (my column name = id) from the incremented column once every script run first:
$select = "
SELECT MAX(id) AS maxid
FROM [tablename]
LIMIT 1
";
(2) Run the MySQL query as you normaly would, and cast the result to integer, e.g.:
$iMaxId = (int) $result[0]->maxid;
(3) After the "INSERT INTO ... ON DUPLICATE KEY UPDATE" query get the last inserted id your prefered way, e.g.:
$iLastInsertId = (int) $db->lastInsertId();
(4) Compare and react: If the lastInsertId is higher than the highest in the table, it's probably an INSERT, right? And vice versa.
if ($iLastInsertId > $iMaxObjektId) {
// IT'S AN INSERT
}
else {
// IT'S AN UPDATE
}
I know it's quick and maybe dirty. And it's an old post. But, hey, I was searching for a solution a for long time, and maybe somebody finds my way somewhat useful anyway. All the best!

In first scenario I supposed that your table have IDENTITY column
CREATE TRIGGER [dbo].[insupddel_yourTable] ON [yourTable]
FOR INSERT, UPDATE, DELETE
AS
IF ##ROWCOUNT = 0 return
SET NOCOUNT ON;
DECLARE #action nvarchar(10)
SELECT #action = CASE WHEN COUNT(i.Id) > COUNT(d.Id) THEN 'inserted'
WHEN COUNT(i.Id) < COUNT(d.Id) THEN 'deleted' ELSE 'updated' END
FROM inserted i FULL JOIN deleted d ON i.Id = d.Id
In second scenario don't need to use IDENTITTY column
CREATE TRIGGER [dbo].[insupddel_yourTable] ON [yourTable]
FOR INSERT, UPDATE, DELETE
AS
IF ##ROWCOUNT = 0 return
SET NOCOUNT ON;
DECLARE #action nvarchar(10),
#insCount int = (SELECT COUNT(*) FROM inserted),
#delCount int = (SELECT COUNT(*) FROM deleted)
SELECT #action = CASE WHEN #insCount > #delCount THEN 'inserted'
WHEN #insCount < #delCount THEN 'deleted' ELSE 'updated' END

DECLARE #INSERTEDCOUNT INT,
#DELETEDCOUNT INT
SELECT #INSERTEDCOUNT = COUNT([YourColumnName]) FROM inserted
SELECT #DELETEDCOUNT = COUNT([YourColumnName]) FROM deleted
IF its updation
#INSERTEDCOUNT = 1
#DELETEDCOUNT = 1
if its insertion
#INSERTEDCOUNT = 1
#DELETEDCOUNT = 0

I've used those exists (select * from inserted/deleted) queries for a long time, but it's still not enough for empty CRUD operations (when there're no records in inserted and deleted tables). So after researching this topic a little bit I've found more precise solution:
declare
#columns_count int = ?? -- number of columns in the table,
#columns_updated_count int = 0
-- this is kind of long way to get number of actually updated columns
-- from columns_updated() mask, it's better to create helper table
-- or at least function in the real system
with cte_columns as (
select #columns_count as n
union all
select n - 1 from cte_columns where n > 1
), cte_bitmasks as (
select
n,
(n - 1) / 8 + 1 as byte_number,
power(2, (n - 1) % 8) as bit_mask
from cte_columns
)
select
#columns_updated_count = count(*)
from cte_bitmasks as c
where
convert(varbinary(1), substring(#columns_updated_mask, c.byte_number, 1)) & c.bit_mask > 0
-- actual check
if exists (select * from inserted)
if exists (select * from deleted)
select #operation = 'U'
else
select #operation = 'I'
else if exists (select * from deleted)
select #operation = 'D'
else if #columns_updated_count = #columns_count
select #operation = 'I'
else if #columns_updated_count > 0
select #operation = 'U'
else
select #operation = 'D'
It's also possible to use columns_updated() & power(2, column_id - 1) > 0 to see if the column is updated, but it's not safe for tables with big number of columns. I've used a bit complex way of calculating (see helpful article below).
Also, this approach will still incorrectly classifies some updates as inserts (if every column in the table is affected by update), and probably it will classifies inserts where there only default values are inserted as deletes, but those are king of rare operations (at lease in my system they are).
Besides that, I don't know how to improve this solution at the moment.
COLUMNS_UPDATED() for audit triggers by Piotr Rodak
Dealing with very large bitmasks by Adam Machanic

declare #result as smallint
declare #delete as smallint = 2
declare #insert as smallint = 4
declare #update as smallint = 6
SELECT #result = POWER(2*(SELECT count(*) from deleted),1) + POWER(2*(SELECT
count(*) from inserted),2)
if (#result & #update = #update)
BEGIN
print 'update'
SET #result=0
END
if (#result & #delete = #delete)
print 'delete'
if (#result & #insert = #insert)
print 'insert'

i do this:
select isnull((select top 1 1 from inserted t1),0) + isnull((select top 1 2 from deleted t1),0)
1 -> insert
2 -> delete
3 -> update
set #i = isnull((select top 1 1 from inserted t1),0) + isnull((select top 1 2 from deleted t1),0)
--select #i
declare #action varchar(1) = case #i when 1 then 'I' when 2 then 'D' when 3 then 'U' end
--select #action
select #action c1,* from inserted t1 where #i in (1,3) union all
select #action c1,* from deleted t1 where #i in (2)

Related

IF NOT EXIST insert ELSE IF update ELSE IF EXISTS and is not Numeric DELETE From WHERE

I want to modify the Stored Procedure below.
#UserID INT
#Unlock VARCHAR(4)
AS
SET NOCOUNT ON
IF NOT EXISTS (SELECT * FROM dbo.tblUnlockCode WHERE iUserID = #UserID)
BEGIN
IF ISNUMERIC(#Unlock) = 1
BEGIN
INSERT dbo.tblUnlockCode (iUserID, sUnlockCode) VALUES (#UserID, #Unlock)
END
I would actually like to add to it, to where if the iUserID exists Update the #Unlock to the new Pin, and if the iUserID exists on the table but the #Unlock gets erased on the textfield(in access) it gets removed from the Table. I only want to store the iUserIDs that 4 digit pins. How could I do that?
P.S. on access I am checking if the pin is 4 digits.
Try this (I also recommend adding error handling if you have none):
#UserID INT
#Unlock VARCHAR(4)
AS
SET NOCOUNT ON
IF NOT EXISTS (SELECT * FROM dbo.tblUnlockCode WHERE iUserID = #UserID)
BEGIN
IF ISNUMERIC(#Unlock) = 1
BEGIN
INSERT dbo.tblUnlockCode (iUserID, sUnlockCode) VALUES (#UserID, #Unlock)
END
END
ELSE
BEGIN
IF ISNUMERIC(#Unlock) = 1
BEGIN
UPDATE dbo.tblUnlockCode set sUnlockCode=#Unlock WHERE iUserID= #UserID
END
ELSE --Assuming you want to clear the record if unlock code is empty
BEGIN
DELETE dbo.tblUnlockCode WHERE iUserID= #UserID
END
END

SQL Trigger Inconsistently firing

I have a SQL Trigger on a table that works... most of the time. And I cannot figure out why sometimes the fields are NULL
The trigger works by Updateing the LastUpdateTime whenever something is modified in the field, and the InsertDatetime when first Created.
For some reason this only seems to work some times.
ALTER TRIGGER [dbo].[DateTriggerTheatreListHeaders]
ON [dbo].[TheatreListHeaders]
AFTER INSERT,UPDATE
AS
BEGIN
SET NOCOUNT ON;
IF NOT EXISTS(SELECT * FROM DELETED)
BEGIN
UPDATE ES
SET InsertDatetime = Getdate()
,LastUpdateDateTime = Getdate()
FROM TheatreListHeaders es
JOIN Inserted I ON es.UNIQUETHEATRELISTNUMBER = I.UNIQUETHEATRELISTNUMBER
END
IF UPDATE(LastUpdateDateTime) OR UPDATE(InsertDatetime)
RETURN;
IF EXISTS (
SELECT
*
FROM
INSERTED I
JOIN
DELETED D
-- make sure to compare inserted with (same) deleted person
ON D.UNIQUETHEATRELISTNUMBER = I.UNIQUETHEATRELISTNUMBER
)
BEGIN
UPDATE ES
SET InsertDatetime = ISNULL(es.Insertdatetime,Getdate())
,LastUpdateDateTime = Getdate()
FROM TheatreListHeaders es
JOIN Inserted I ON es.UNIQUETHEATRELISTNUMBER = I.UNIQUETHEATRELISTNUMBER
END
END
A much simpler and efficient approach to do what you are trying to do, would be something like...
ALTER TRIGGER [dbo].[DateTriggerTheatreListHeaders]
ON [dbo].[TheatreListHeaders]
AFTER INSERT,UPDATE
AS
BEGIN
SET NOCOUNT ON;
--Determine if this is an INSERT OR UPDATE Action .
DECLARE #Action as char(1);
SET #Action = (CASE WHEN EXISTS(SELECT * FROM INSERTED)
AND EXISTS(SELECT * FROM DELETED)
THEN 'U' -- Set Action to Updated.
WHEN EXISTS(SELECT * FROM INSERTED)
THEN 'I' -- Set Action to Insert.
END);
UPDATE ES
SET InsertDatetime = CASE WHEN #Action = 'U'
THEN ISNULL(es.Insertdatetime,Getdate())
ELSE Getdate()
END
,LastUpdateDateTime = Getdate()
FROM TheatreListHeaders es
JOIN Inserted I ON es.UNIQUETHEATRELISTNUMBER = I.UNIQUETHEATRELISTNUMBER;
END
"If update()" is poorly defined/implemented in sql server IMO. It does not do what is implied. The function only determines if the column was set by a value in the triggering statement. For an insert, every column is implicitly (if not explicitly) assigned a value. Therefore it is not useful in an insert trigger and difficult to use in a single trigger that supports both inserts and updates. Sometimes it is better to write separate triggers.
Are you aware of recursive triggers? An insert statement will execute your trigger which updates the same table. This causes the trigger to execute again, etc. Is the (database) recursive trigger option off (which is typical) or adjust your logic to support that?
What are your expectations for the insert/update/merge statements against this table? This goes back to your requirements. Is the trigger to ignore any attempt to set the datetime columns directly and set them within the trigger always?
And lastly, what exactly does "works sometimes" actually mean? Do you have a test case that reproduces your issue. If you don't, then you can't really "fix" the logic without a specific failure case. But the above comments should give you sufficient clues. To be honest, your logic seems to be overly complicated. I'll add that it also is logically flawed in the way that it set insertdatetime to getdate if the existing value is null during an update. IMO, it should reject any update that attempts to set the value to null because that is overwriting a fact that should never change. M.Ali has provided an example that is usable but includes the created timestamp problem. Below is an example that demonstrates a different path (assuming the recursive trigger option is off). It does not include the rejection logic - which you should consider. Notice the output of the merge execution carefully.
use tempdb;
set nocount on;
go
create table zork (id integer identity(1, 1) not null primary key,
descr varchar(20) not null default('zippy'),
created datetime null, modified datetime null);
go
create trigger zorktgr on zork for insert, update as
begin
declare #rc int = ##rowcount;
if #rc = 0 return;
set nocount on;
if update(created)
select 'created column updated', #rc as rc;
else
select 'created column NOT updated', #rc as rc;
if exists (select * from deleted) -- update :: do not rely on ##rowcount
update zork set modified = getdate()
where exists (select * from inserted as ins where ins.id = zork.id);
else
update zork set created = getdate(), modified = getdate()
where exists (select * from inserted as ins where ins.id = zork.id);
end;
go
insert zork default values;
select * from zork;
insert zork (descr) values ('bonk');
select * from zork;
update zork set created = null, descr = 'upd #1' where id = 1;
select * from zork;
update zork set descr = 'upd #2' where id = 1;
select * from zork;
waitfor delay '00:00:02';
merge zork as tgt
using (select 1 as id, 'zippity' as descr union all select 5, 'who me?') as src
on tgt.id = src.id
when matched then update set descr = src.descr
when not matched then insert (descr) values (src.descr)
;
select * from zork;
go
drop table zork;

mssql trigger - selecting specific data from the INSERTED table

I got an Audit table to track the insert / update operations.
My problem is that on update there are 2 cases.
1) regular update
2) update to a field called Isdeleted from false to true.
I tried to separate both of the cases but i am missing something, i am new to triggers.
DECLARE #Action AS CHAR(1)
DECLARE #Count AS INT
SET #Action = 'I'
SELECT #Count = COUNT(*) FROM DELETED
if #Count > 0
BEGIN
SET #Action = 'D'
SELECT #Count = COUNT(*) FROM INSERTED WHERE INSERTED.IsDeleted = 0
IF #Count > 0
SET #Action = 'U'
END
What i want to do is to get to Action = 'D' when the only value that was changed was IsDeleted ( from false to true ).
And 'U' when any of the other values were changed.
Depending on how you created your trigger, you can modify it to make use of UPDATE() to simplify the logic of setting the value of #Action.
For example:
CREATE TRIGGER myTrigger ON myTable AFTER UPDATE, DELETE
BEGIN
DECLARE #Action AS CHAR(1)
IF UPDATE(isDeleted)
SET #Action = 'U'
END
This will fire everytime but only SET the value of #Action when there is a change on the isDeleted column, which I think is what you're looking for.
I'm not sure what you're going to do with this onward, but it will do what you need.
This select will return the number of rows that the IsDeleted column was updated from 0 to 1:
select count(*)
from inserted inner join deleted on <fk_column(s)>
where deleted.IsDeleted = 0
and inserted.IsDeleted = 1
However, since triggers works per statement (and not per row), there could be cases where some rows are deleted and some are just updated, so keeping the action per row might be a little more tricky then that.
try This :
DECLARE #Action AS CHAR(1)
DECLARE #Count AS INT
IF NOT EXISTS(SELECT 1 FROM Deleted)
BEGIN
SELECT
#Action = 'I'
END
ELSE
BEGIN
SELECT
#Count = COUNT(1)
FROM Inserted Ins
INNER JOIN Deleted Del
ON Ins.SeqNo = Del.SeqNo
WHERE ISNULL(Ins.IsDeleted,0) <> ISNULL(Del.IsDeleted,0)
AND Ins.Column1 = Del.Column1
AND Ins.Column2 = Del.Column2
AND Ins.ColumnN = Del.ColumnN
SELECT
#Action = CASE WHEN ISNULL(#Count,0)>0
THEN 'D'
ELSE 'U' END
END
SELECT
[ActionCode] = #Action

T-SQL Trigger - prevent duplicate, but not always

I would like to avoid INSERTS and UPDATES which could duplicate field's value, but not always.
I have a varchar field Cat_Catalog. in table Catalog.
I can have two rows with Cat_Catalog's value "123" duplicated, but I cannot have duplicated field Cat_Catalog which starts with 'KAT' word (so I cannot have 2 rows with "KAT123" Cat_Catalog's value)
The following trigger i made doesn't work fine because field that's going to be updated starts with KAT trigger always raise error (variable #IfExist always return true - it is probably because of AFTER UPDATE,INSERT syntax).
I would like to avoid using INSTEAD OF syntax because updates are generated by some API which to i have no documentation and I'm not sure what to do in case when value doesn't starts with 'KAT'.
GO
/****** Object: Trigger [dbo].[Catalog_InsertUpdateCatalog] ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
--If first three characters are 'KAT'
--then check for duplicate and raiseerror
ALTER TRIGGER [dbo].[Catalog_InsertUpdateCatalog] ON [dbo].[Catalog]
FOR UPDATE,INSERT
AS
set nocount on;
DECLARE #CatalogInsert varchar(50)
DECLARE #IfKat varchar(10) = 'FALSE'
DECLARE #IfExist varchar(10) = 'FALSE'
SELECT #CatalogInsert = Cat_Catalog
FROM inserted
--Does It starts with 'KAT' ?
IF (#CatalogInsert like 'KAT%')
BEGIN
SET #IfKat = 'TRUE'
END
--Check for Duplicate
IF EXISTS(
Select * from Test.dbo.Catalog t
where t.Cat_Catalog = #CatalogInsert
)
BEGIN
SET #IfExist = 'TRUE'
END
IF ( #IfExist = 'TRUE' and #IfKat = 'TRUE' )
BEGIN
RAISERROR ('Catalog allready exists: %s , ISKAT:%s , EXIST:%s', 16, 1, #CatalogInsert, #IfKat, #IfExist);
END
`
The problem is that I don't know how can I check the current value to be updated allready exists in Catalog table (check must be done before update).
Using CHECK constraint instead of a trigger would be a better solution, since triggers are executed much later in the transaction and eventual rollback could be expensive. You can define check constraint as follows:
CREATE FUNCTION IsDuplicate(#col varchar(50))
RETURNS BIT
AS
BEGIN
IF CHARINDEX('KAT', #col) = 1 AND (SELECT COUNT(*) FROM [Catalog] WHERE [Cat_Catalog] = #col) > 1
return 1;
return 0;
END;
GO
ALTER TABLE [Catalog]
ADD CONSTRAINT chkForDuplicates CHECK (dbo.IsDuplicate([Cat_Catalog]) = 0)
GO
Have in mind that if you already have duplicate "KATxxx" values in the table you'll have to either delete them or create the constraint with NOCHECK clause.
Please, try this new version:
ALTER TRIGGER [dbo].[Catalog_InsertUpdateCatalog] ON [dbo].[Catalog]
FOR UPDATE,INSERT
AS BEGIN
set nocount on;
--Check for Duplicate
IF EXISTS(
Select 1
From (
-- Updated
SELECT
COUNT(*) OVER (PARTITION BY Cat_Catalog) Cnt,
Cat_Catalog
FROM dbo.Catalog
WHERE
Cat_Catalog LIKE 'KAT%'
) t
Join inserted i ON t.Cat_Catalog = i.Cat_Catalog AND Cnt > 1
)
BEGIN
RAISERROR ('Catalog allready exists!', 16, 1);
ROLLBACK TRANSACTION;
END
END
This trigger check the existence of rows with the same [Cat_Catalog] field as in the inserted (or updated) rows. If duplicated rows exists and [Cat_Catalog] starts with 'KAT' trigger RAISE error + rollback transaction.
UPDATED: I change trigger. It should now work correctly (i test it). Trigger FOR UPDATE, INSERT fires after changes take place in table. So we need check duplicate rows in the table.
I do it throught COUNT(*) OVER(PARTITION BY Cat_Catalog) but you may check it in a more familiar way:
SELECT
COUNT(*) Cnt,
Cat_Catalog
FROM
dbo._Catalog
WHERE
Cat_Catalog LIKE 'KAT%'
GROUP BY
Cat_Catalog
Use Instead OF Trigger instead After Trigger.
If your problem with Instead OF Triggers, then you need to use NOT Eqals operator to avoid such wrong indication to passed. I supposed to say
DECLARE #CATALOG_PK BIGINT;
SELECT #CATALOG_PK = CATALOG_PK FROM INSERTED
--Check for Duplicate
IF EXISTS(
Select * from Test.dbo.Catalog t
where t.Cat_Catalog = #CatalogInsert
AND CATALOG_PK <>#CATELOG_PK LIKE t.CATALOG LIKE 'KAT%'
)
BEGIN
SET #IfExist = 'TRUE'
END
However this will fail in-case of multiple UPDATES or INSERTS done.
Try these two triggers:
CREATE TRIGGER [MyCatalog_InsertCatalog] ON [dbo].[MyCatalog]
FOR INSERT
AS
IF EXISTS(
SELECT I.*
FROM Inserted I
INNER JOIN MyCatalog M
ON M.Cat_Catalog = I.Cat_Catalog
WHERE I.Cat_Catalog LIKE 'KAT%' )
BEGIN
RAISERROR ('Insert Catalog already exists: ', 16, 1);
ROLLBACK TRANSACTION;
END
GO
CREATE TRIGGER [MyCatalog_UpdateCatalog] ON [dbo].[MyCatalog]
FOR UPDATE
AS
IF EXISTS(
SELECT I.*
FROM Inserted I
INNER JOIN MyCatalog M
ON M.Cat_Catalog = I.Cat_Catalog
INNER JOIN deleted d
ON d.Cat_Id = i.Cat_Id
WHERE I.Cat_Catalog LIKE 'KAT%' AND d.Cat_Catalog <> i.Cat_Catalog)
BEGIN
RAISERROR ('Update Catalog already exists: ', 16, 1);
ROLLBACK TRANSACTION;
END
EDIT
You could combine both triggers into one:
CREATE TRIGGER [MyCatalog_InsertUpdateCatalog] ON [dbo].[MyCatalog]
FOR INSERT, UPDATE
AS
IF EXISTS(
SELECT I.*
FROM Inserted I
INNER JOIN MyCatalog M
ON M.Cat_Catalog = I.Cat_Catalog
INNER JOIN deleted d
ON d.Cat_Id = i.Cat_Id
WHERE I.Cat_Catalog LIKE 'KAT%' AND d.Cat_Catalog <> i.Cat_Catalog)
BEGIN
RAISERROR ('Update Catalog already exists: ', 16, 1);
ROLLBACK TRANSACTION;
END
ELSE BEGIN
IF EXISTS(
SELECT I.*
FROM Inserted I
INNER JOIN MyCatalog M
ON M.Cat_Catalog = I.Cat_Catalog
WHERE I.Cat_Catalog LIKE 'KAT%' )
BEGIN
RAISERROR ('Insert Catalog already exists: ', 16, 1);
ROLLBACK TRANSACTION;
END
END

Trigger store information duplicate

I am using Trigger & this trigger is fire on the table when i am fill the information by UI Form. First time it is inserting the record proper in the table.
Again update it the information then it is store two records in the tables.
Mean Two Rows are inserted in the table against update. What I am doing wrong in Trigger.
My Trigger is given below:
ALTER TRIGGER [dbo].[trPkgDPRBidSubmissionDetails]
ON [dbo].[tblPkgDPRBidSubmissionDetails]
AFTER insert, update, delete
AS
BEGIN
DECLARE #Action as varchar(50);
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
SET #Action = 'Insert'; -- Set Action to Insert by default.
IF EXISTS(SELECT * FROM DELETED)
BEGIN
SET #Action =
CASE
WHEN EXISTS(SELECT * FROM INSERTED) THEN 'UPDATE'
ELSE 'DELETE'
END
END
if( #Action = 'DELETE')
begin
insert into tblPkgDPRBidSubmissionDetailsAT(iUserId,cAction, dtAction,iActionOwner,iPackage,dtInitialDesignReport,dtDPR, dtBidDocuments,dtExternalReview1,dtComplianceToPWD1,dtComplianceToExtAgency1,dtExternalReview2,dtComplianceToPWD2,dtComplianceToExtAgency2, dtApprovalFromExternalAgency,dtIFB,dtUpToIssue,dtPreMeeting,dtBidOpeningMeetingOriginal, dtBidOpeningMeetingExtension1,dtBidOpeningMeetingExtension2,dtBidOpeningMeetingExtension3, iNumberOfBidsSold,iNumberOfBidsReceived)
select iUserId,#Action, getdate(), 1,iPackage,dtInitialDesignReport, dtDPR, dtBidDocuments,dtExternalReview1, dtComplianceToPWD1,dtComplianceToExtAgency1,dtExternalReview2,dtComplianceToPWD2,dtComplianceToExtAgency2,dtApprovalFromExternalAgency, dtIFB,dtUpToIssue,dtPreMeeting,dtBidOpeningMeetingOriginal,dtBidOpeningMeetingExtension1,dtBidOpeningMeetingExtension2,dtBidOpeningMeetingExtension3, iNumberOfBidsSold,iNumberOfBidsReceived
from deleted;
end
else
begin
insert into tblPkgDPRBidSubmissionDetailsAT(iUserId,cAction, dtAction,iActionOwner,iPackage,dtInitialDesignReport,dtDPR, dtBidDocuments,dtExternalReview1,dtComplianceToPWD1,dtComplianceToExtAgency1,dtExternalReview2,dtComplianceToPWD2,dtComplianceToExtAgency2, dtApprovalFromExternalAgency,dtIFB,dtUpToIssue,dtPreMeeting,dtBidOpeningMeetingOriginal, dtBidOpeningMeetingExtension1,dtBidOpeningMeetingExtension2, dtBidOpeningMeetingExtension3,iNumberOfBidsSold,iNumberOfBidsReceived)
select iUserId,#Action, getdate(), 1,iPackage,dtInitialDesignReport, dtDPR, dtBidDocuments,dtExternalReview1, dtComplianceToPWD1,dtComplianceToExtAgency1,dtExternalReview2,dtComplianceToPWD2,dtComplianceToExtAgency2,dtApprovalFromExternalAgency, dtIFB,dtUpToIssue,dtPreMeeting,dtBidOpeningMeetingOriginal,dtBidOpeningMeetingExtension1,dtBidOpeningMeetingExtension2,dtBidOpeningMeetingExtension3, iNumberOfBidsSold,iNumberOfBidsReceived
from inserted;
end
-- Insert statements for trigger here
-- action owner field to be udpated
END
The code inside your ELSE block handles both INSERT and UPDATE actions, so you end up with another row inserted into tblPkgDPRBidSubmissionDetailsAT table in both cases.
I think this is what you need:
if( #Action = 'DELETE')
begin
insert into tblPkgDPRBidSubmissionDetailsAT(iUserId,cAction, dtAction,iActionOwner,iPackage,dtInitialDesignReport,dtDPR, dtBidDocuments,dtExternalReview1,dtComplianceToPWD1,dtComplianceToExtAgency1,dtExternalReview2,dtComplianceToPWD2,dtComplianceToExtAgency2, dtApprovalFromExternalAgency,dtIFB,dtUpToIssue,dtPreMeeting,dtBidOpeningMeetingOriginal, dtBidOpeningMeetingExtension1,dtBidOpeningMeetingExtension2,dtBidOpeningMeetingExtension3, iNumberOfBidsSold,iNumberOfBidsReceived)
select iUserId,#Action, getdate(), 1,iPackage,dtInitialDesignReport, dtDPR, dtBidDocuments,dtExternalReview1, dtComplianceToPWD1,dtComplianceToExtAgency1,dtExternalReview2,dtComplianceToPWD2,dtComplianceToExtAgency2,dtApprovalFromExternalAgency, dtIFB,dtUpToIssue,dtPreMeeting,dtBidOpeningMeetingOriginal,dtBidOpeningMeetingExtension1,dtBidOpeningMeetingExtension2,dtBidOpeningMeetingExtension3, iNumberOfBidsSold,iNumberOfBidsReceived
from deleted;
end
else
begin
if #Action = 'INSERT'
insert into tblPkgDPRBidSubmissionDetailsAT(iUserId,cAction, dtAction,iActionOwner,iPackage,dtInitialDesignReport,dtDPR, dtBidDocuments,dtExternalReview1,dtComplianceToPWD1,dtComplianceToExtAgency1,dtExternalReview2,dtComplianceToPWD2,dtComplianceToExtAgency2, dtApprovalFromExternalAgency,dtIFB,dtUpToIssue,dtPreMeeting,dtBidOpeningMeetingOriginal, dtBidOpeningMeetingExtension1,dtBidOpeningMeetingExtension2, dtBidOpeningMeetingExtension3,iNumberOfBidsSold,iNumberOfBidsReceived)
select iUserId,#Action, getdate(), 1,iPackage,dtInitialDesignReport, dtDPR, dtBidDocuments,dtExternalReview1, dtComplianceToPWD1,dtComplianceToExtAgency1,dtExternalReview2,dtComplianceToPWD2,dtComplianceToExtAgency2,dtApprovalFromExternalAgency, dtIFB,dtUpToIssue,dtPreMeeting,dtBidOpeningMeetingOriginal,dtBidOpeningMeetingExtension1,dtBidOpeningMeetingExtension2,dtBidOpeningMeetingExtension3, iNumberOfBidsSold,iNumberOfBidsReceived
from inserted;
end

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