I've got two tables that are linked with foreign keys. I need to do a few inserts on one table and then use the identity column values are part of my next batch of insert statements. This all has to be done through SQL.
I've been reading about SCOPE_IDENTITY() but all the examples I'm seeing are using ASP/PHP/Whatever to do the substitution in the next batch of inserts, I dont have this option.
Any pointers appreciated.
Use
SCOPE_IDENTITY() - Function
instead of
##IDENTITY Variable -
otherwise you get the result of the last inserted identity - if there is a trigger on the table than does inserting somewhere you get the wrong result back (the value inserted by the trigger and not by your statement). Scope_Identity returns the identity of your statement and that is what you normally want.
IN SQl Server 2008 you can also use the OUTPUT clause.
DECLARE #output TABLE (myid INT)
INSERT mytable (field1, field2)
OUTPUT inserted.myid INTO #output
VALUES ('test', 'test')
SELECT * FROM #output
What makes this espcially valuable is if you use it to insert a bunch of records instead of one you can get all the identities, You can also return any of the other fields you might need.
something like:
DECLARE #output TABLE (myid INT, field1 datetime)
INSERT mytable (field1, field2)
OUTPUT inserted.myid, inserted.field1 INTO #output
Select '20100101', field3 from mytable2
SELECT * FROM #output
You can do the same with SQL or TSQL. Just assign the identify column as soon as you do the insert.
-- Variable to hold new Id
Declare #NewId int
--Insert some values in to create a new ID
Insert Into dbo.MyTable1 (Col1)
Values (#NewValue)
-- Grab the new Id and store it in the variable
Select #NewId = Scope_Identity()
--Insert the new Id in to another table
Insert Into dbo.AnotherTable (Col1)
Values (#NewId)
You can use
SELECT SCOPE_IDENTITY() [Iden]
After the insert statement in the same block. This should work.
Related
My database contains three tables called Object_Table, Data_Table and Link_Table. The link table just contains two columns, the identity of an object record and an identity of a data record.
I want to copy the data from DATA_TABLE where it is linked to one given object identity and insert corresponding records into Data_Table and Link_Table for a different given object identity.
I can do this by selecting into a table variable and the looping through doing two inserts for each iteration.
Is this the best way to do it?
Edit : I want to avoid a loop for two reason, the first is that I'm lazy and a loop/temp table requires more code, more code means more places to make a mistake and the second reason is a concern about performance.
I can copy all the data in one insert but how do get the link table to link to the new data records where each record has a new id?
In one statement: No.
In one transaction: Yes
BEGIN TRANSACTION
DECLARE #DataID int;
INSERT INTO DataTable (Column1 ...) VALUES (....);
SELECT #DataID = scope_identity();
INSERT INTO LinkTable VALUES (#ObjectID, #DataID);
COMMIT
The good news is that the above code is also guaranteed to be atomic, and can be sent to the server from a client application with one sql string in a single function call as if it were one statement. You could also apply a trigger to one table to get the effect of a single insert. However, it's ultimately still two statements and you probably don't want to run the trigger for every insert.
You still need two INSERT statements, but it sounds like you want to get the IDENTITY from the first insert and use it in the second, in which case, you might want to look into OUTPUT or OUTPUT INTO: http://msdn.microsoft.com/en-us/library/ms177564.aspx
The following sets up the situation I had, using table variables.
DECLARE #Object_Table TABLE
(
Id INT NOT NULL PRIMARY KEY
)
DECLARE #Link_Table TABLE
(
ObjectId INT NOT NULL,
DataId INT NOT NULL
)
DECLARE #Data_Table TABLE
(
Id INT NOT NULL Identity(1,1),
Data VARCHAR(50) NOT NULL
)
-- create two objects '1' and '2'
INSERT INTO #Object_Table (Id) VALUES (1)
INSERT INTO #Object_Table (Id) VALUES (2)
-- create some data
INSERT INTO #Data_Table (Data) VALUES ('Data One')
INSERT INTO #Data_Table (Data) VALUES ('Data Two')
-- link all data to first object
INSERT INTO #Link_Table (ObjectId, DataId)
SELECT Objects.Id, Data.Id
FROM #Object_Table AS Objects, #Data_Table AS Data
WHERE Objects.Id = 1
Thanks to another answer that pointed me towards the OUTPUT clause I can demonstrate a solution:
-- now I want to copy the data from from object 1 to object 2 without looping
INSERT INTO #Data_Table (Data)
OUTPUT 2, INSERTED.Id INTO #Link_Table (ObjectId, DataId)
SELECT Data.Data
FROM #Data_Table AS Data INNER JOIN #Link_Table AS Link ON Data.Id = Link.DataId
INNER JOIN #Object_Table AS Objects ON Link.ObjectId = Objects.Id
WHERE Objects.Id = 1
It turns out however that it is not that simple in real life because of the following error
the OUTPUT INTO clause cannot be on
either side of a (primary key, foreign
key) relationship
I can still OUTPUT INTO a temp table and then finish with normal insert. So I can avoid my loop but I cannot avoid the temp table.
I want to stress on using
SET XACT_ABORT ON;
for the MSSQL transaction with multiple sql statements.
See: https://msdn.microsoft.com/en-us/library/ms188792.aspx
They provide a very good example.
So, the final code should look like the following:
SET XACT_ABORT ON;
BEGIN TRANSACTION
DECLARE #DataID int;
INSERT INTO DataTable (Column1 ...) VALUES (....);
SELECT #DataID = scope_identity();
INSERT INTO LinkTable VALUES (#ObjectID, #DataID);
COMMIT
It sounds like the Link table captures the many:many relationship between the Object table and Data table.
My suggestion is to use a stored procedure to manage the transactions. When you want to insert to the Object or Data table perform your inserts, get the new IDs and insert them to the Link table.
This allows all of your logic to remain encapsulated in one easy to call sproc.
If you want the actions to be more or less atomic, I would make sure to wrap them in a transaction. That way you can be sure both happened or both didn't happen as needed.
You might create a View selecting the column names required by your insert statement, add an INSTEAD OF INSERT Trigger, and insert into this view.
Before being able to do a multitable insert in Oracle, you could use a trick involving an insert into a view that had an INSTEAD OF trigger defined on it to perform the inserts. Can this be done in SQL Server?
Insert can only operate on one table at a time. Multiple Inserts have to have multiple statements.
I don't know that you need to do the looping through a table variable - can't you just use a mass insert into one table, then the mass insert into the other?
By the way - I am guessing you mean copy the data from Object_Table; otherwise the question does not make sense.
//if you want to insert the same as first table
$qry = "INSERT INTO table (one, two, three) VALUES('$one','$two','$three')";
$result = #mysql_query($qry);
$qry2 = "INSERT INTO table2 (one,two, three) VVALUES('$one','$two','$three')";
$result = #mysql_query($qry2);
//or if you want to insert certain parts of table one
$qry = "INSERT INTO table (one, two, three) VALUES('$one','$two','$three')";
$result = #mysql_query($qry);
$qry2 = "INSERT INTO table2 (two) VALUES('$two')";
$result = #mysql_query($qry2);
//i know it looks too good to be right, but it works and you can keep adding query's just change the
"$qry"-number and number in #mysql_query($qry"")
I have 17 tables this has worked in.
-- ================================================
-- Template generated from Template Explorer using:
-- Create Procedure (New Menu).SQL
--
-- Use the Specify Values for Template Parameters
-- command (Ctrl-Shift-M) to fill in the parameter
-- values below.
--
-- This block of comments will not be included in
-- the definition of the procedure.
-- ================================================
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE InsetIntoTwoTable
(
#name nvarchar(50),
#Email nvarchar(50)
)
AS
BEGIN
SET NOCOUNT ON;
insert into dbo.info(name) values (#name)
insert into dbo.login(Email) values (#Email)
END
GO
I am a bit confused by the documentation & behavior of SCOPE_IDENTITY() in SQL Server.
This page https://learn.microsoft.com/en-us/sql/t-sql/functions/scope-identity-transact-sql?view=sql-server-2017 says this about SCOPE_IDENTITY():
Returns the last identity value inserted into an identity column in
the same scope. A scope is a module: a stored procedure, trigger,
function, or batch. Therefore, if two statements are in the same
stored procedure, function, or batch, they are in the same scope.
And it contains this example
USE AdventureWorks2012;
GO
INSERT INTO Person.ContactType ([Name]) VALUES ('Assistant to the Manager');
GO
SELECT SCOPE_IDENTITY() AS [SCOPE_IDENTITY];
GO
SELECT ##IDENTITY AS [##IDENTITY];
GO
Which returns
SCOPE_IDENTITY
21
##IDENTITY
21
From the docs I would have thought that the result of SCOPE_IDENTITY() would be NULL because SELECT SCOPE_IDENTITY() AS [SCOPE_IDENTITY]; is executed in a different batch (because it comes after GO) than the INSERT command... What am I missing here?
I'd agree, I think the documentation is slightly misleading. SCOPE_IDENTITY does retain its value across multiple batches directly executed on the same connection.
But note that if you create an inner batch, by executing EXEC with a string, that inner batch's SCOPE_IDENTITY is independent from your outer batch's SCOPE_IDENTITY
This script produces the value 2, not 5:
create table T1 (ID int IDENTITY(2,1000) not null,Val char(1))
create table T2 (ID int IDENTITY(5,1000) not null, Val char(1))
go
insert into T1(Val) values ('a')
exec('insert into T2(Val) values (''b'')')
select SCOPE_IDENTITY()
Don't use scope_indentity. SQL Server has a much, much better way of returning values from the insert, the OUTPUT clause.
DECLARE #ids TABLE (id INT);
INSERT INTO Person.ContactType ([Name])
OUTPUT inserted.ID INTO #ids -- I'm not sure what the identity is named
VALUES ('Assistant to the Manager');
This has multiple advantages:
You can return more columns than just the id.
You can return the ids from inserts that have more than one row.
You don't have to worry about scoping at all.
I have two tables that are identical except one has an identity column and the other doesn't. Instead the second table uses the value of the identity column from the first table. I thought I would insert into the second table as a trigger when a record is inserted into the first table. I cannot seem to get syntax right.
Null is being returned from the identity column #EDVisitId.
ALTER TRIGGER [dbo].[trgInserterrEDVisitOriginal] ON [dbo].[errEDVisit]
AFTER INSERT
AS
--Name: Bob Avallone
--Date: 6-15-2017
--
-- The purpose of this trigger is to insert a record into errEDVisitOriginal
-- whenever a new errEDVisit is inserted.
--XXXXXXXXXX
declare #EDVisitId int
declare #SubmissionControlID INT
Select #EDVisitId = EDVisitID from inserted
SELECT #SubmissionControlID = SubmissionControlID from Inserted
Begin
Insert Into errEDVisitOriginal (EDVisitId, SubmissionControlID)
VALUES (#EDVisitId, #SubmissionControlID )
End
Thanks for all the suggestions. I abandoned the idea of a trigger. Instead I simply insert the new records from the first table into the second one. See below.
Insert errEDVisitOriginal(EdVisitId, SubmissionControlID)
Select EdVisitId, SubmissionControlID
from errEDVisit where SubmissionControlID = #SubmissionControlID
you just need scope_identity()
Select #EDVisitId = scope_identity()
You can use SCOPE_IDENTITY to get the last inserted id from the first table put it into a variable then insert into the second table.
https://learn.microsoft.com/en-us/sql/t-sql/functions/scope-identity-transact-sql
Though the decision to duplicate information intentionally is dubious, you are vastly over-thinking the code. Just:
if exists (select * from inserted)
insert dbo.errEDVisitOriginal (EDVisitId, SubmissionControlID)
select EDVisitId, SubmissionControlID from inserted;
I have a sql query which inserts a lot of new rows in table and updates a lot of old rows.
Is there a way to determine all rows which where inserted?
Found this in a previous Stackoverflow article:
How to insert multiple records and get the identity value?
Below is by Andy Irving:
Use the ouput clause from 2005:
DECLARE #output TABLE (id int)
Insert into A (fname, lname)
OUTPUT inserted.ID INTO #output
SELECT fname, lname FROM B
select * from #output
now your table variable has the identity values of all the rows you insert.
Hi did you try something like execute
SELECT ##IDENTITY
after execute INSERT statement?
Take a look at this
##IDENTITY is deprecated, You would be recommended to use SCOPE_IDENTITY()
You can also determine the inserted items via the inserted table
I'm going to insert data into a table like so:
Insert Into MyTable (Field1, Field2)
Values ('test', 5)
When that insert occurs, the new row is going to have an identify value in the ID column. If have a variable called #ID in my T-SQL code, how do I populate #ID with the result of the T-SQL Insert?
Declare #ID int
Insert into MyTable (Field1, Field2)
Values ('test', 5)
--//How do I populate #ID with the value of ID of the record that was just inserted?
There are two ways - the first is to use SCOPE_IDENTITY:
DECLARE #ID INT
INSERT INTO MyTable (Field1, Field2)
VALUES ('test', 5)
SELECT #ID = SCOPE_IDENTITY()
Don't use ##IDENTITY -- the value it contains is for the last updated IDENTITY column without regard for scope. Meaning, it's not reliable that it holds the value for your INSERT, but SCOPE_IDENTITY does.
The other alternative is to use the OUTPUT clause (SQL Server 2005+).
SELECT #ID = SCOPE_IDENTITY();
You should use scope_identity in your case.
There are different ways to get last inserted identity and they differ in how they work just for your information listing them -
##IDENTITY
SCOPE_IDENTITY()
IDENT_CURRENT
OUTPUT CLAUSE (came to know about it from #OMG Ponies answer)
Consider the differences and comparisons between them before deciding which one to use.