I have an existing table with thousands of records, with primary key, foreign key and relationships. I have to set the primary key column to be identity, but I don't want to start it from 0 because the table has existing records, and I also don't want to lose data.
I must to save the exact table design.
I have to add an identity, and reseed it.
What should I do?
Thank you!
Just update table with IDs. Then Choose current max ID to execute
DBCC CHECKIDENT ('MyTable', RESEED, maxId)
More about reseeding
You cannot add identity to existing table. Identity has to be specified as part of table creation. You have two options.
Recreate new table with identity properly set up with reseed value & Set up IDENTITY_INSERT ON & Insert existing rows to new table & IDENTITY_INSERT OFF.
CREATE TABLE [dbo].[NewTable](
[ID] [int] IDENTITY(1000,1) NOT NULL PRIMARY KEY, -- 1000 is Reseed value
Col1
Col2
);
-- SET IDENTITY_INSERT to ON.
SET IDENTITY_INSERT dbo.NewTable ON;
GO
INSERT INTO NewTable(Id,col1,col2...)
SELECT Id, col1, col2... FROM oldtable;
GO
SET IDENTITY_INSERT dbo.NewTable OFF;
GO
Create a sequence with starting value as the reseed value and use the sequence for your future insertions.
CREATE SEQUENCE dbo.TestSeq
START WITH 1000 -- Reseed value
INCREMENT BY 1 ;
GO
INSERT Test.TestTable (ID, Col1, Col2,...)
VALUES (NEXT VALUE FOR dbo.TestSeq, 1, 2,...) ;
GO
I found the solution:
At SSMS -> Tools -> Options -> Designers: Remove the V from 'Prevent Saving changes that require table re-creation'.
Open the table in Design Mode, and add the V to the Identity Spcification property.
This will also reseed it automatically.
Related
I have a MS SQL 2005 database with a table Test with column ID. ID is an identity column.
I have rows in this table and all of them have their corresponding ID auto incremented value.
Now I would like to change every ID in this table like this:
ID = ID + 1
But when I do this I get an error:
Cannot update identity column 'ID'.
I've tried this:
ALTER TABLE Test NOCHECK CONSTRAINT ALL
set identity_insert ID ON
But this does not solve the problem.
I need to have identity set to this column, but I need to change values as well from time to time. So my question is how to accomplish this task.
You need to
set identity_insert YourTable ON
Then delete your row and reinsert it with different identity.
Once you have done the insert don't forget to turn identity_insert off
set identity_insert YourTable OFF
IDENTITY column values are immutable.
However it is possible to switch the table metadata to remove the IDENTITY property, do the update, then switch back.
Assuming the following structure
CREATE TABLE Test
(
ID INT IDENTITY(1,1) PRIMARY KEY,
X VARCHAR(10)
)
INSERT INTO Test
OUTPUT INSERTED.*
SELECT 'Foo' UNION ALL
SELECT 'Bar' UNION ALL
SELECT 'Baz'
Then you can do
/*Define table with same structure but no IDENTITY*/
CREATE TABLE Temp
(
ID INT PRIMARY KEY,
X VARCHAR(10)
)
/*Switch table metadata to new structure*/
ALTER TABLE Test SWITCH TO Temp;
/*Do the update*/
UPDATE Temp SET ID = ID + 1;
/*Switch table metadata back*/
ALTER TABLE Temp SWITCH TO Test;
/*ID values have been updated*/
SELECT *
FROM Test
/*Safety check in case error in preceding step*/
IF NOT EXISTS(SELECT * FROM Temp)
DROP TABLE Temp /*Drop obsolete table*/
In SQL Server 2012 it is possible to have an auto incrementing column that can also be updated more straightforwardly with SEQUENCES
CREATE SEQUENCE Seq
AS INT
START WITH 1
INCREMENT BY 1
CREATE TABLE Test2
(
ID INT DEFAULT NEXT VALUE FOR Seq NOT NULL PRIMARY KEY,
X VARCHAR(10)
)
INSERT INTO Test2(X)
SELECT 'Foo' UNION ALL
SELECT 'Bar' UNION ALL
SELECT 'Baz'
UPDATE Test2 SET ID+=1
Through the UI in SQL Server 2005 manager, change the column remove the autonumber (identity) property of the column (select the table by right clicking on it and choose "Design").
Then run your query:
UPDATE table SET Id = Id + 1
Then go and add the autonumber property back to the column.
Firstly the setting of IDENTITY_INSERT on or off for that matter will not work for what you require (it is used for inserting new values, such as plugging gaps).
Doing the operation through the GUI just creates a temporary table, copies all the data across to a new table without an identity field, and renames the table.
This can be done using a temporary table.
The idea
disable constraints (in case your id is referenced by a foreign key)
create a temp table with the new id
delete the table content
copy back data from the copied table to your original table
enable previsously disabled constraints
SQL Queries
Let's say your test table have two additional columns (column2 and column3) and that there are 2 tables having foreign keys referencing test called foreign_table1 and foreign_table2 (because real life issues are never simple).
alter table test nocheck constraint all;
alter table foreign_table1 nocheck constraint all;
alter table foreign_table2 nocheck constraint all;
set identity_insert test on;
select id + 1 as id, column2, column3 into test_copy from test v;
delete from test;
insert into test(id, column2, column3)
select id, column2, column3 from test_copy
alter table test check constraint all;
alter table foreign_table1 check constraint all;
alter table foreign_table2 check constraint all;
set identity_insert test off;
drop table test_copy;
That's it.
DBCC CHECKIDENT ( ‘databasename.dbo.orders’,RESEED, 999)
you can change any identity column number with this command,and also you can start that field number from every number you want.for example in my command i ask to start from 1000 (999+1)
hope that it would be enough...good luck
If the column is not a PK you could always create a NEW column in the table with the incremented numbers, drop the original and then alter the new one to be the old.
curious as to why you might need to do this... most I've ever had to futz with Identity columns was to backfill numbers and I just ended up using DBCC CHECKIDENT ( tablename,RESEED,newnextnumber)
good luck!
Identity modifying may fail depending on a number of factors, mainly revolving around the objects/relationships linked to the id column. It seems like db design is as issue here as id's should rarely if ever change (i'm sure you have your reasons and are cascasding the changes). If you really need to change id's from time to time, I'd suggest either creating a new dummy id column that isn't the primary key/autonumber that you can manage yourself and generate from the current values. Alternately, Chrisotphers idea above would be my other suggestion if you're having issues with allowing identity insert.
Good luck
PS it's not failing because the sequential order it's running in is trying to update a value in the list to an item that already exists in the list of ids? clutching at straws, perhaps add the number of rows+1, then if that works subtract the number of rows :-S
If you need to change the IDs occasionally, it's probably best not to use an identity column. In the past we've implemented autonumber fields manually using a 'Counters' table that tracks the next ID for each table. IIRC we did this because identity columns were causing database corruption in SQL2000 but being able to change IDs was occasionally useful for testing.
You can insert new rows with modified values and then delete old rows. Following example change ID to be same as foreign key PersonId
SET IDENTITY_INSERT [PersonApiLogin] ON
INSERT INTO [PersonApiLogin](
[Id]
,[PersonId]
,[ApiId]
,[Hash]
,[Password]
,[SoftwareKey]
,[LoggedIn]
,[LastAccess])
SELECT [PersonId]
,[PersonId]
,[ApiId]
,[Hash]
,[Password]
,[SoftwareKey]
,[LoggedIn]
,[LastAccess]
FROM [db304].[dbo].[PersonApiLogin]
GO
DELETE FROM [PersonApiLogin]
WHERE [PersonId] <> ID
GO
SET IDENTITY_INSERT [PersonApiLogin] OFF
GO
First save all IDs and alter them programmatically to the values you wan't, then remove them from database and then insert them again using something similar:
use [Name.Database]
go
set identity_insert [Test] ON
insert into [dbo].[Test]
([Id])
VALUES
(2)
set identity_insert [Test] OFF
For bulk insert use:
use [Name.Database]
go
set identity_insert [Test] ON
BULK INSERT [Test]
FROM 'C:\Users\Oscar\file.csv'
WITH (FIELDTERMINATOR = ';',
ROWTERMINATOR = '\n',
KEEPIDENTITY)
set identity_insert [Test] OFF
Sample data from file.csv:
2;
3;
4;
5;
6;
If you don't set identity_insert to off you will get the following error:
Cannot insert explicit value for identity column in table 'Test' when
IDENTITY_INSERT is set to OFF.
I saw a good article which helped me out at the last moment .. I was trying to insert few rows in a table which had identity column but did it wrongly and have to delete back. Once I deleted the rows then my identity column got changed . I was trying to find an way to update the column which was inserted but - no luck. So, while searching on google found a link ..
Deleted the columns which was wrongly inserted
Use force insert using identity on/off (explained below)
http://beyondrelational.com/modules/2/blogs/28/posts/10337/sql-server-how-do-i-insert-an-explicit-value-into-an-identity-column-how-do-i-update-the-value-of-an.aspx
Very nice question, first we need to on the IDENTITY_INSERT for the specific table, after that run the insert query (Must specify the column name).
Note: After edit the the identity column, don't forget to off the IDENTITY_INSERT. If you not done, you cannot able to Edit the identity column for any other table.
SET IDENTITY_INSERT Emp_tb_gb_Menu ON
INSERT Emp_tb_gb_Menu(MenuID) VALUES (68)
SET IDENTITY_INSERT Emp_tb_gb_Menu OFF
http://allinworld99.blogspot.com/2016/07/how-to-edit-identity-field-in-sql.html
I've had to import some data into a db using IDENTITY_INSERT ON, do I set it back to OFF after the import? what is it's default setting? Obviously I need the application to add records/rows to the tables making a new ID each time.
Default setting depends on how you defined the identity column when you created the table
for example
CREATE TABLE Table_Name(ID INT IDENTITY(1,1))
GO
this ID column will have a Seed value of 1 and increment by 1.
By default you cannot add values to Identity column but you can change this default behaviour by executing the following statement.
SET IDENTITY_INSERT Table_Name ON;
Once you have inserted the values then you can set it back to its default behaviour by executing the following statement.
SET IDENTITY_INSERT Table_Name OFF;
even though we can pass values to Identity column but its not a good practice, since it is an auto generated number, if you add the values into identity column yourself and then Identity column generates the same number later on you can have duplicates in your identity column.
so its best to leave identity column alone, and let it generate the values for you.
if it is necessary to add values to Identity column then I would recommend executing the following statement after every you have Indet_Insert ON and add some values to Identity column,
DBCC CHECKIDENT ( table_name, RESEED, 0)
DBCC CHECKIDENT ( table_name, RESEED)
The 1st statement will RESEED the value of Identity column to the smallest values in your identity column,
2nd RESEED statement with out any Seed value provided, will reseed the Identity value to the next available value to the highest value in your identity column.
In case of someone searching for a way to create a key without identity column:
CREATE TABLE [dbo].[TableName](
[Id] [int] NOT NULL PRIMARY KEY
)
instead of
CREATE TABLE [dbo].[TableName](
[Id] [int] IDENTITY(1,1) NOT NULL
)
I have a table A with an Identity Column which is the primary key.
The primary key is at the same time a foreign key that points towards another table B.
I am trying to build an insert trigger that inserts into Table B the identity column that is about to be created in table A and another custom value for example '1'.
I tried using ##Identity but I keep getting a foreign key conflict. Thanks for your help.
create TRIGGER dbo.tr ON dbo.TableA FOR INSERT
AS
SET NOCOUNT ON
begin
insert into TableB
select ##identity, 1;
end
alexolb answered the question himself in the comments above. Another alternative is to use the IDENT_CURRENT function instead of selecting from the table. The drawback of this approach is that it always starts your number one higher than the seed, but that is easily remedied by setting the seed one unit lower. I think it feels better to use a function than a subquery.
For example:
CREATE TABLE [tbl_TiggeredTable](
[id] [int] identity(0,1) NOT NULL,
[other] [varchar](max)
)
CREATE TRIGGER [trgMyTrigger]
ON [tbl_TriggeredTable]
INSTEAD OF INSERT,UPDATE,DELETE
SET identity_insert tbl_TriggeredTable ON
INSERT INTO tbl_TriggeredTable (
[id],
[other]
)
SELECT
-- The identity column will have a zero in the insert table when
-- it has not been populated yet, so we need to figure it out manually
case i.[id]
when 0 then IDENT_CURRENT('tbl_TriggeredTable') + IDENT_INCR('tbl_TriggeredTable')
ELSE i.[id]
END,
i.[other],
FROM inserted i
SET identity_insert tbl_TriggeredTable OFF
END
How can I modify table and set identity on PK column using T-SQL?
thanks for help
You can't modify an existing column to have the IDENTITY "property" - you have to:
create a new table with the same structure (but with IDENTITY set up),
turn on IDENTITY_INSERT for this new table,
insert rows from the old table into the new table,
drop the old table, and,
rename the new table to have the old table name.
If there are foreign keys involved, you need to fix those up also.
The problem with most solutions to this question is that they require either adding a new column to the table or completely rebuilding the table.
Both can require large amounts of locking and logging activity which I have always found annoying as this is a metadata only change and shouldn't necessitate touching the data pages at all (Indeed it is possible to update the metadata directly by starting the instance in single user mode and messing around with some columns in sys.syscolpars but this is undocumented/unsupported.)
However the workaround posted on this connect item shows a completely supported way of making this into a metadata only change using ALTER TABLE...SWITCH (credit SQLKiwi)
Example code.
Set up test table with no identity column.
CREATE TABLE dbo.tblFoo
(
bar INT PRIMARY KEY,
filler CHAR(8000),
filler2 CHAR(49)
)
INSERT INTO dbo.tblFoo (bar)
SELECT TOP (10000) ROW_NUMBER() OVER (ORDER BY (SELECT 0))
FROM master..spt_values v1, master..spt_values v2
Alter it to have an identity column (more or less instant).
BEGIN TRY;
BEGIN TRANSACTION;
/*Using DBCC CHECKIDENT('dbo.tblFoo') is slow so use dynamic SQL to
set the correct seed in the table definition instead*/
DECLARE #TableScript nvarchar(max)
SELECT #TableScript =
'
CREATE TABLE dbo.Destination(
bar INT IDENTITY(' +
CAST(ISNULL(MAX(bar),0)+1 AS VARCHAR) + ',1) PRIMARY KEY,
filler CHAR(8000),
filler2 CHAR(49)
)
ALTER TABLE dbo.tblFoo SWITCH TO dbo.Destination;
'
FROM dbo.tblFoo
WITH (TABLOCKX,HOLDLOCK)
EXEC(#TableScript)
DROP TABLE dbo.tblFoo;
EXECUTE sp_rename N'dbo.Destination', N'tblFoo', 'OBJECT';
COMMIT TRANSACTION;
END TRY
BEGIN CATCH
IF XACT_STATE() <> 0 ROLLBACK TRANSACTION;
PRINT ERROR_MESSAGE();
END CATCH;
Test the result.
INSERT INTO dbo.tblFoo (filler,filler2)
OUTPUT inserted.*
VALUES ('foo','bar')
Gives
bar filler filler2
----------- --------- ---------
10001 foo bar
Clean up
DROP TABLE dbo.tblFoo
Is it the answer you are looking for?
DBCC CHECKIDENT(
'DBName.dbo.TableName'
,RESEED --[, new_reseed_value ]
)
Example use:
DBCC CHECKIDENT(
'DBName.dbo.TableName'
)
Checking identity information: current identity value '1', current column value '1211031236'.
DBCC execution completed. If DBCC printed error messages, contact your system administrator.
DBCC CHECKIDENT(
'DBName.dbo.TableName'
,RESEED --[, new_reseed_value ]
)
Checking identity information: current identity value '1211031236', current column value '1211031236'.
DBCC execution completed. If DBCC printed error messages, contact your system administrator.
In fact, you can modify the IDENTITY on a column.
Please read through this article http://www.sqlmag.com/article/tsql3/adding-the-identity-property-to-an-existing-column.aspx
It will need a lot more code than ALTER TABLE tab ALTER COLUMN col SET IDENTITY, though
You need to use the ALTER TABLE command - always test first in dev or pre-production!
The example G seems closest to your requirement:
CREATE TABLE dbo.doc_exe ( column_a INT CONSTRAINT column_a_un UNIQUE) ;
GO
ALTER TABLE dbo.doc_exe ADD
-- Add a PRIMARY KEY identity column.
column_b INT IDENTITY
CONSTRAINT column_b_pk PRIMARY KEY,
See http://msdn.microsoft.com/en-us/library/ms190273.aspx
Since you can only ignore identity columns for insert, not for update, you'll need an intermediate table. Here's an example:
create table TestTable (pk int constraint PK_TestTable primary key,
name varchar(30))
create table TestTable2 (pk int constraint PK_TestTable identity primary key,
name varchar(30))
set identity_insert TestTable2 on
insert TestTable2 (pk, name) select pk, name from TestTable
set identity_insert TestTable2 off
drop table TestTable
exec sp_rename 'TestTable2', 'TestTable'
I have a table with column ID that is identity one. Next I create new non-identity column new_ID and update it with values from ID column + 1. Like this:
new_ID = ID + 1
Next I drop ID column and rename new_ID to name 'ID'.
And how to set Identity on this new column 'ID'?
I would like to do this programmatically!
As far as I know, you have to create a temporary table with the ID field created as IDENTITY, then copy all the data from the original table. Finally, you drop the original table and rename the temporary one. This is an example with a table (named TestTable) that contains only one field, called ID (integer, non IDENTITY):
BEGIN TRANSACTION
GO
CREATE TABLE dbo.Tmp_TestTable
(
ID int NOT NULL IDENTITY (1, 1)
) ON [PRIMARY]
GO
SET IDENTITY_INSERT dbo.Tmp_TestTable ON
GO
IF EXISTS(SELECT * FROM dbo.TestTable)
EXEC('INSERT INTO dbo.Tmp_TestTable (ID)
SELECT ID FROM dbo.TestTable WITH (HOLDLOCK TABLOCKX)')
GO
SET IDENTITY_INSERT dbo.Tmp_TestTable OFF
GO
DROP TABLE dbo.TestTable
GO
EXECUTE sp_rename N'dbo.Tmp_TestTable', N'TestTable', 'OBJECT'
GO
COMMIT
Looks like SQL Mobile supports altering a columns identity but on SQL Server 2005 didn't like the example from BOL.
So your options are to create a new temporary table with the identity column, then turn Identity Insert on:
Create Table Tmp_MyTable ( Id int identity....)
SET IDENTITY_INSERT dbo.Tmp_Category ON
INSERT Into Tmp_MyTable (...)
Select From MyTable ....
Drop Table myTable
EXECUTE sp_rename N'dbo.Tmp_MyTable', N'MyTable', 'OBJECT'
Additionally you can try and add the column as an identity column in the first place and then turn identity insert on. Then drop the original column. But I am not sure if this will work.
Guessing you didn't have much luck with your task....
In table design, you should be able to go into properties and under Identity Specification change (Is Identity) to Yes and assign the column primary key if it formerly had the primary key.
From SqlServerCentral.com
Changing from Non-IDENTITY to IDENTITY and vice versa
An Identity is a property that is set at the time the table is created or a new column is added in alter table statement. You can't alter the column and set it to identity and it is impossible to have two identity columns within the same table.
Depending on the size of the table, is it possible to simply create a new table? copy over the schema of the old one and then use SET IDENTITY_INSERT ON to populate the new identity column with what you want from the old one.