How use inserted\deleted table in stored procedure? - sql

I creating triggers for several tables. The triggers have same logic. I will want to use a common stored procedure.
But I don't know how work with inserted and deleted table.
example:
SET #FiledId = (SELECT FiledId FROM inserted)
begin tran
update table with (serializable) set DateVersion = GETDATE()
where FiledId = #FiledId
if ##rowcount = 0
begin
insert table (FiledId) values (#FiledId)
end
commit tran

You can use a table valued parameter to store the inserted / deleted values from triggers, and pass it across to the proc. e.g., if all you need in your proc is the UNIQUE FileID's:
CREATE TYPE FileIds AS TABLE
(
FileId INT
);
-- Create the proc to use the type as a TVP
CREATE PROC commonProc(#FileIds AS FileIds READONLY)
AS
BEGIN
UPDATE at
SET at.DateVersion = CURRENT_TIMESTAMP
FROM ATable at
JOIN #FileIds fi
ON at.FileID = fi.FileID;
END
And then pass the inserted / deleted ids from the trigger, e.g.:
CREATE TRIGGER MyTrigger ON SomeTable FOR INSERT
AS
BEGIN
DECLARE #FileIds FileIDs;
INSERT INTO #FileIds(FileID)
SELECT DISTINCT FileID FROM INSERTED;
EXEC commonProc #FileIds;
END;

You can
select * into #Inserted from inserted
select * into #Deleted from deleted
and then
use these two temp tables in your stored proc

The tables inserted and deleted are only available inside the trigger. You can only use them in run-time. They will then contain the affected rows.
Also, your code might not work as expected if there is not exactly one row inserted.

Related

Microsoft SQL Server - default value provided by stored procedure

Is it possible to have a non-null column where the value is generated at insert by calling a stored procedure the parameters of which are values passed to insert into the row?
For example, I have table User:
| username | name | surname | id |
Insert looks like this:
INSERT INTO USER (username, name, surname)
VALUES ('myusername', 'myname', 'mysurname');
The id column is populated with an (integer) value retrieved by calling stored procedure mystoredproc with parameters myusername, myname, mysurname.
A further question is, would this stored procedure be called on each row, or can it be called in a grouped fashion. For example, I'd like my stored procedure to take the name and append a random integer to it so that that if I insert 100 users with the name 'David', they will get the same id and the stored procedure will be called only once. A bit of a bad example on the second point.
Good day,
Is it possible to have a non-null column where the value is generated at insert by calling a stored procedure
Option 1: please check if this work for you
Specify Default Value for the Column and use "NOT NULL"
create trigger on the table AFTER INSERT
Inside the trigger, you can use the virtual table "inserted" in order to get the inserted values.
Using these values (using the inserted table) you can update the column using the logic you need for all the rows at once
** there is no need to use external SP probably, but you can execute SP from trigger if needed
** All executed by a trigger is in the same transaction as the original query.
would this stored procedure be called on each row
NO! The trigger will be executed once for all rows you insert in the same statement. The inserted table includes all the rows which were inserted. In your update section (step 4) you can update all the rows which were inserted in once and no need to execute something for each row
** If you do use external SP which is executed from the trigger then you can pass it all the inserted table as one using Table-Valued Parameter
------------------- update ---------------
Here is a full example of using this logic:
drop table if exists T;
CREATE TABLE T (id int identity(2,2), c int NOT NULL default 1)
GO
CREATE TRIGGER tr ON T AFTER INSERT
AS BEGIN
SET NOCOUNT ON;
UPDATE T SET T.c = T2.C + 1
FROM inserted T2
INNER JOIN T T1 ON T1.id = T2.id
END
INSERT T(c) values (1) -- I insert the value 1 but the trigger will change it to 1+1=2
select * from T
GO
-- test multiple rows:
INSERT T(c) values (10),(20),(30),(40)
select * from T
GO
DECLARE #rc INT = 0,
#UserID INT = ABS(CHECKSUM(NEWID())) % 1000000 + 1;
WHILE #rc = 0
BEGIN
IF NOT EXISTS (SELECT 1 FROM dbo.Users WHERE UserId= #UserId)
BEGIN
INSERT dbo.Users(UserId) WHERE Username = #UserName SELECT #UserId;
SET #rc = 1;
END
ELSE
BEGIN
SELECT #UserId = ABS(CHECKSUM(NEWID())) % 1000000 + 1,
#rc = 0;
END
END

Delete trigger and getting field from another table

I have this delete trigger on an SQL database. The record deletes currently and gets written to an audit table. I have been asked to include in this history table a field from another table that is related to the record being deleted based on SurveyID. I thought I could do something like
select #Status = Status from table where Survey = deleted.Survey
But this is incorrect syntax.
ALTER trigger [dbo].[table_Selfdelete]
on [dbo].[table]
after delete
as
Begin
Set nocount on;
Declare #SurveyId int
Declare #StudentUIC varchar(10)
Declare #Status varchar(10)
select #SurveyId = deleted.SurveyID,
#StudentUIC = deleted.StudentUIC
from deleted
select #Status = Status from tbly when SurveyID = deleted.SurveyID
insert into fupSurveyAudit
values(#SurveyId,#StudentUIC,#Status)
End
Arrgh. I think you want this insert in your trigger (and nothing else):
insert into fupSurveyAudit(SurveyId, StudentUIC, status)
select d.SurveyId, d.StudentUIC, y.status
from deleted d left join
tbly y
on d.SurveyId = y.SurveyId;
Notes:
deleted could contain more than one row, so assuming that it has one row can lead to a run-time error or incorrect results.
A left join is needed in case there is no matching row for the status.
You should always include the columns in an insert
Your archive table should have additional columns, such as an identity column and the date of the insert, which are set automatically (and hence not explicitly part of the insert).
Triggers are fired once for each statement (Delete,insert,update) not for each row inside the statement.
You cannot use variables here because when multiple lines are deleted from the table only one line will be inserted in the Audit table because the variable can only hold one value.
You just need a simple insert from the deleted table into the Audit table something like this....
ALTER trigger [dbo].[table_Selfdelete]
on [dbo].[table]
after delete
as
Begin
Set nocount on;
insert into fupSurveyAudit(SurveyId, StudentUIC,[Status])
select d.SurveyID
,d.StudentUIC
,y.[Status]
from deleted d
INNER JOIN tbly y ON y.SurveyID = deleted.SurveyID
End
Try this
ALTER trigger [dbo].[table_Selfdelete]
on [dbo].[table]
after delete
as
Begin
Set nocount on;
insert into fupSurveyAudit -- Better listed the column list here
select
d.SurveyID, d.StudentUIC, y.Status
from
deleted d JOIN tbly y ON d.SurveyID = y.SurveyID
End

Insert data into table when i am using trigger?

Here is a trigger
CREATE TRIGGER [dbo].[CheckApplyId]
ON [dbo].[AppliedStudent_event] INSTEAD OF INSERT
AS
DECLARE #studentId INT
DECLARE #compReq_Id INT
BEGIN
SELECT #studentId = studentId
FROM INSERTED
SELECT #compReq_Id = compReq_Id
FROM INSERTED
IF EXISTS(SELECT StudentId,
compreq_id
FROM AppliedStudent_event
WHERE StudentId = #studentId
AND compreq_id = #compReq_Id)
BEGIN
ROLLBACK
PRINT 'User Already Applied'
END
END
When in insert a data into a table using command:
INSERT INTO AppliedStudent_event (StudentId, compreq_id)
VALUES (3026, 1)
Message is:
(1 row(s) affected)
But when I execute a sql command no data is inserted in the table.
Can you please tell why are you using trigger because you use only assign the variable #studentId and #compReq_Id from inserted table.
That's a broken trigger because inserted can contain multiple (or no) rows - so a statement like SELECT #ScalarVariable = column from inserted is always wrong.
And it's unnecessary since you can just place a UNIQUE constraint on the StudentId and compreq_id columns:
ALTER TABLE AppliedStudent_event
ADD CONSTRAINT UQ_Student_Events
UNIQUE (StudentId,compreq_id)
And it's further broken because you've specified it as an instead of trigger - that says that your code is going to be responsible for the actual insert - but your code doesn't actually do that. That's why no data ends up in the table.
If you insist on doing it as a trigger, it's actually tricky to get everything correct (that's why I'd really recommend the UNIQUE constraint). It'll end up being something like this:
CREATE TRIGGER [dbo].[CheckApplyId]
ON [dbo].[AppliedStudent_event] INSTEAD OF INSERT
AS
IF EXISTS(select
StudentId,compreq_id,COUNT(*)
from inserted
group by StudentId,compreq_id
HAVING COUNT(*) > 1)
OR EXISTS (select *
from inserted i
inner join
AppliedStudent_event e
on
i.StudentId = e.StudentId and
i.compreq_id = e.compreq_id)
BEGIN
ROLLBACK
PRINT 'User Already Applied'
END
ELSE
BEGIN
INSERT INTO AppliedStudent_event(StudentId,compreq_id /* Other columns? */)
SELECT StudentId,compreq_id /* And again, other columns */
FROM inserted
END

Updating a Table after some values are inserted into it in SQL Server 2008

I am trying to write a stored procedure in SQL Server 2008 which updates a table after some values are inserted into the table.
My stored procedure takes the values from a DMV and stores them in a table. In the same procedure after insert query, I have written an update query for the same table.
Insert results are populated fine, but the results of updates are getting lost.
But when I try to do only inserts in the stored procedure and I execute the update query manually everything is fine.
Why it is happening like this?
there should not be a problem in this.
below code working as expected.
create procedure dbo.test
as
begin
create table #temp (
name varchar(100) ,
id int
)
insert #temp
select name ,
id
from master..sysobjects
update #temp
set name='ALL Same'
from #temp
select * from #temp
drop table #temp
end
go
Best approach is to use Trigger, sample of AFTER UPDATE trigger is below:
ALTER TRIGGER [dbo].[tr_MyTriggerName]
ON [dbo].[MyTableName] AFTER UPDATE
AS
BEGIN
SET NOCOUNT ON;
--if MyColumnName is updated the do..
IF UPDATE (MyColumnName)
BEGIN
UPDATE MyTableName
SET AnotherColumnInMyTable = someValue
FROM MyTableName
INNER JOIN Inserted
ON MyTableName.PrimaryKeyColumn = Inserted.PrimaryKeyColumn
END
END

Can a storeProcecdure insert fire Trigger?

SQL Server 2008
I have trigger defined on
TABLE_A for 'INSTEAD OF INSERT' and TABLE_B for 'INSTEAD OF INSERT'.
Both the triggers perform merge with the inserted table.
TABLE_A insert is done by user/code and is working well, trigger for insert is fired.
I have Stored procedure SP_1 inside TABLE_A TRIGGER.
SP_1 Inserts data from TABLE_A into TABLE_B based on some conditions.
But the problem is when the stored procedure (SP_1) is inserting data, the trigger on TABLE_B is not fired and the data is just inserted as it is.
So can stored procedure inserts fire triggers?
Pseudo-code
ALTER TRIGGER [dbo].[trgtable_AInsert] ON [dbo].[TABLE_A]
Instead of INSERT
AS
BEGIN
SET NOCOUNT ON;
IF exists(SELECT * FROM INSERTED)
BEGIN
MERGE
.......
...........
..............
end
EXEC SP_1 #employee_id
end
ALTER TRIGGER [dbo].[trgtableB_Insert] ON [dbo].[TABLE_B]
Instead of INSERT
AS
BEGIN
SET NOCOUNT ON;
IF exists(SELECT * FROM INSERTED)
BEGIN
MERGE
.......
...........
..............
end
end
ALTER PROCEDURE [dbo].[SP_1] #employeeid int
AS
BEGIN
BEGIN TRANSACTION
insert into TABLE_B
.......
...........
..............
from TABLE_A
where employee_ID is #employeeid
COMMIT TRANSACTION
END
Yes triggers can fired by stored procedure inserts!
But I think the problem is that you should try to use AFTER instead of INSTEAD OF triggers in this case. Becasue I can't see all of your code, but it is possible, that the insert is not done because you overrided it in the Instead Of triggers. With AFTER triggers you should have no problems with firing the second trigger.
This is too big for a comment, and needs formatting, so posting as an "answer".
Yes, triggers will fire in this case. Taking your example and slightly modifying it (note the warnings though):
create table Table_A (ID int not null)
go
create table Table_B (ID int not null)
GO
CREATE PROCEDURE [dbo].[SP_1] #employeeid int
AS
BEGIN
BEGIN TRANSACTION
insert into TABLE_B (ID)
SELECT ID from TABLE_A
where ID = #employeeid
COMMIT TRANSACTION
END
GO
Creating the triggers:
CREATE TRIGGER [dbo].[trgtable_AInsert] ON [dbo].[TABLE_A]
Instead of INSERT
AS
BEGIN
SET NOCOUNT ON;
IF exists(SELECT * FROM INSERTED)
BEGIN
MERGE
into Table_A a
using inserted i on a.id = i.id
when not matched then insert (ID) values (i.id);
end
--Wrong code, just for example
declare #employee_id int
select #employee_id = ID from inserted --BAD CODE, Ignores multiple rows
EXEC SP_1 #employee_id
end
GO
CREATE TRIGGER [dbo].[trgtableB_Insert] ON [dbo].[TABLE_B]
Instead of INSERT
AS
BEGIN
SET NOCOUNT ON;
IF exists(SELECT * FROM INSERTED)
BEGIN
MERGE
into Table_B b
using inserted i on b.id = i.id
when not matched then insert (ID) values (i.id+5);
end
end
GO
And executing a trial insert into Table_A:
insert into Table_A (ID) values (1),(2)
select * from Table_B
On my machine, at the present time, I get a final result of a single row with the value "7". Others may run this sample and get the result "6", because triggers only run once per statement, rather than once per row. But as you can see, both triggers have fired.
As i previously mentioned in the comments #András Ottó
Merge
using(... = "column with possible null values" AND
... = ... AND
... = ...
)
of merge was not working correctly and the records were always inserted.
1 = 1 and E=E and NULL=NULL is not true. (of-course sql 101)
I have overlooked this column and did not place where clause properly to get rid of null values so ended up inserting all the time. Fixing that everything ended up working.
Thanks for the help Every1. Cheers
Apologies.
I'm not going to mark it answered because it is purely my mistake which was not fully mentioned in the question.