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'd like to store a set of data into a database but if it's a pre-existing record, I'd like to alter it. Otherwise, create a new one. Is there a combine statement for that? (Haven't got any when googling.)
Right now, the best I have is to check if already exists and then perform one of the operations. Seems cumbersome to me.
create table Stuff (
Id int identity(1001, 1) primary key clustered,
Beep int unique,
Boop nvarchar(50))
IN MYSQL :
You may use INSERT ... ON DUPLICATE KEY UPDATE .
eg:
INSERT INTO table (a,b,c) VALUES (4,5,6)
ON DUPLICATE KEY UPDATE c=9;
For more information: http://dev.mysql.com/doc/refman/5.6/en/insert-on-duplicate.html
MySQL uses INSERT... ON DUPLICATE KEY and MSSQL uses MERGE
MERGE is supported by Azure, and I can highly recommend this blog article on it, as a good intro to the statement
Here is a merge statement based on the schema provided...
create table #Stuff (
Id int identity(1001, 1) primary key clustered,
Beep int unique,
Boop nvarchar(50),
Baap nvarchar(50)
);
INSERT INTO #Stuff VALUES (1,'boop', 'poop');
INSERT INTO #Stuff VALUES (2,'beep', 'peep');
SELECT * FROM #STUFF;
MERGE #Stuff
USING (VALUES(1,'BeepBeep','PeepPeep')) AS TheNewThing(A,B,C)
ON #Stuff.Beep = TheNewThing.A
WHEN MATCHED THEN UPDATE SET #Stuff.Boop = TheNewThing.B, #Stuff.Baap = 'fixed'
WHEN NOT MATCHED THEN INSERT (Beep,Boop,Baap) VALUES (
TheNewThing.A, TheNewThing.B, TheNewThing.C);
SELECT * FROM #STUFF
I also found a really good SO Q which might make good further reading
yes you can easily do it using pl/sql here is sample code which will help you
http://docs.oracle.com/cd/B10501_01/appdev.920/a96624/01_oview.htm#7106
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
I'm creating a table that'll have a single bit not null column IsDefault. I need to write a constraint that'll make sure there'll be only one default value per UserId (field in the same table).
I can't use unique constraint on this because it is possible to have many non-default values.
What is the best approach to do this using MS SQL Server 2008?
Thanks.
The easiest way I see is a check constraint with a UDF (User Defined function).
Look at here, for example.
http://sqljourney.wordpress.com/2010/06/25/check-constraint-with-user-defined-function-in-sql-server/
Untested example
CREATE FUNCTION dbo.CheckDefaultUnicity(#UserId int)
RETURNS int
AS
BEGIN
DECLARE #retval int
SELECT #retval = COUNT(*) FROM <your table> where UserId = #UserId and <columnwithDefault> = 1-- or whatever is your default value
RETURN #retval
END;
GO
and alter your table
ALTER TABLE <yourTable>
ADD CONSTRAINT Ck_UniqueDefaultForUser
CHECK (dbo.CheckDefaultUnicity(UserId) <2)
Another relatively simple option is to use a CLUSTERED INDEXED VIEW. The gist of this is to
Select all UserID's from your table where IsDefault=1 in a view.
Add a unique index on UserID
Clustered indexed view
CREATE VIEW dbo.VIEW_Users_IsDefault WITH SCHEMABINDING AS
SELECT UserID, IsDefault
FROM dbo.Users
WHERE IsDefault = 1
GO
CREATE UNIQUE CLUSTERED INDEX UIX_VIEW_USERS_ISDEFAULT
ON dbo.VIEW_Users_IsDefault (UserID)
GO
Test script
BEGIN TRAN
CREATE TABLE dbo.Users (UserID INT, IsDefault BIT)
GO
CREATE VIEW dbo.VIEW_Users_IsDefault WITH SCHEMABINDING AS
SELECT UserID, IsDefault
FROM dbo.Users
WHERE IsDefault = 1
GO
CREATE UNIQUE CLUSTERED INDEX UIX_VIEW_USERS_ISDEFAULT ON dbo.VIEW_Users_IsDefault (UserID)
GO
INSERT INTO dbo.Users VALUES (1, 0)
INSERT INTO dbo.Users VALUES (1, 1)
INSERT INTO dbo.Users VALUES (1, 1) -- Fails because of clustered index
ROLLBACK TRAN
A Check Constraint would definitely work, however it's not good a design choice in my opinion. The reason being that your UDF for the constraint would be something like
SELECT #Count = COUNT(UserId)
FROM User
WHERE IsDefault = 1
GROUP BY UserId
HAVING COUNT(UserId) > 1
IF #Count > 0
....'FAIL
As this touches 2 columns it would thus need to be a Table level constraint and the more records you have the slower a Insert/Update/Delete will take.
A better option would be to only allow access to that table via Stored Procedure, so before an insert/update you could run a very quick
IF EXISTS(SELECT UserId FROM User where UserId = #UserId and IsDefault = 1)
before your inserts/updates/deletes
I can however appreciate that you may be using an ORM and might not want to have Stored Procs in your system so you could change the design of your table to the below. This assumes that
tblUser: UserId, FirstName, Suraname, etc
tblUserDefault: UserId (Unique Constraint)
I'm not sure what IsDefault represents in your system so I'm assuming in the above that Users are either default or not. Anybody you can use that as a reference. It allows you to enforce the constraint without using USP's or horrid tablewide check constraints (or triggers) and would be mappable in any decent ORM
What about CHECK Constraints. See here: http://msdn.microsoft.com/en-us/library/ms188258(v=sql.105).aspx
ALTER TABLE yourtable
ADD CONSTRAINT IsDefaultChecked CHECK (IsDefault = T );
While I think the trigger and constraint solutions are better, if you control insert/update via stored procedure a much simpler approach would be to just update the conflicting rows first (assuming the new default always wins):
ALTER PROCEDURE dbo.UserWhateverTable_<action>
#UserID INT,
#CardID INT
AS
BEGIN
SET NOCOUNT ON;
UPDATE dbo.UserWhatever
SET IsDefault = 0
WHERE UserID = #UserID
AND CardID = #CardID
AND IsDefault = 1;
-- insert or update here
END
GO
In fact it might not be a bad idea to do this (so the business logic is 100% clear in your DML procedures) in addition to guarding it with a trigger or a constraint (to catch cases where updates are made outside of your procedures).
You might want to use a trigger in this case. When the user is changing their default, the trigger could automatically flip the current default for the current user to false.
Basically, use an AFTER insert/update trigger to set the IsDefault column to 0 for any user in the insert/update where the IsDefault value is being set to 1.
CREATE TRIGGER dbo.tr_default
ON dbo.MyTable
AFTER INSERT, UPDATE
AS
if(exists(select * from inserted where IsDefault = 1)
begin
update dbo.MyTable
set IsDefault = 0
from inserted i
join dbo.MyTable t on i.userid = t.userid
where i.IsDefault = 1
and i.TheValue != t.TheValue
end
I don't see any problem with any of the answers so far suggesting CHECK CONSTRAINTS and TRIGGERS however, it seems like a bit of a backwards solution to me.
I can only assume UserID in your table is a foreign key to a User table, so why not add a column to your User table to store the default CardID, rather than marking one as default? This makes it impossible for a user to have multiple default CardIDs without costly triggers/constraints. If you make the column non nullable then it is also impossible for a user not to have a default CardID if you so wish.
How could I set a constraint on a table so that only one of the records has its isDefault bit field set to 1?
The constraint is not table scope, but one default per set of rows, specified by a FormID.
Use a unique filtered index
On SQL Server 2008 or higher you can simply use a unique filtered index
CREATE UNIQUE INDEX IX_TableName_FormID_isDefault
ON TableName(FormID)
WHERE isDefault = 1
Where the table is
CREATE TABLE TableName(
FormID INT NOT NULL,
isDefault BIT NOT NULL
)
For example if you try to insert many rows with the same FormID and isDefault set to 1 you will have this error:
Cannot insert duplicate key row in object 'dbo.TableName' with unique
index 'IX_TableName_FormID_isDefault'. The duplicate key value is (1).
Source: http://technet.microsoft.com/en-us/library/cc280372.aspx
Here's a modification of Damien_The_Unbeliever's solution that allows one default per FormID.
CREATE VIEW form_defaults
AS
SELECT FormID
FROM whatever
WHERE isDefault = 1
GO
CREATE UNIQUE CLUSTERED INDEX ix_form_defaults on form_defaults (FormID)
GO
But the serious relational folks will tell you this information should just be in another table.
CREATE TABLE form
FormID int NOT NULL PRIMARY KEY
DefaultWhateverID int FOREIGN KEY REFERENCES Whatever(ID)
From a normalization perspective, this would be an inefficient way of storing a single fact.
I would opt to hold this information at a higher level, by storing (in a different table) a foreign key to the identifier of the row which is considered to be the default.
CREATE TABLE [dbo].[Foo](
[Id] [int] NOT NULL,
CONSTRAINT [PK_Foo] PRIMARY KEY CLUSTERED
(
[Id] ASC
) ON [PRIMARY]
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[DefaultSettings](
[DefaultFoo] [int] NULL
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[DefaultSettings] WITH CHECK ADD CONSTRAINT [FK_DefaultSettings_Foo] FOREIGN KEY([DefaultFoo])
REFERENCES [dbo].[Foo] ([Id])
GO
ALTER TABLE [dbo].[DefaultSettings] CHECK CONSTRAINT [FK_DefaultSettings_Foo]
GO
You could use an insert/update trigger.
Within the trigger after an insert or update, if the count of rows with isDefault = 1 is more than 1, then rollback the transaction.
CREATE VIEW vOnlyOneDefault
AS
SELECT 1 as Lock
FROM <underlying table>
WHERE Default = 1
GO
CREATE UNIQUE CLUSTERED INDEX IX_vOnlyOneDefault on vOnlyOneDefault (Lock)
GO
You'll need to have the right ANSI settings turned on for this.
I don't know about SQLServer.But if it supports Function-Based Indexes like in Oracle, I hope this can be translated, if not, sorry.
You can do an index like this on suposed that default value is 1234, the column is DEFAULT_COLUMN and ID_COLUMN is the primary key:
CREATE
UNIQUE
INDEX only_one_default
ON my_table
( DECODE(DEFAULT_COLUMN, 1234, -1, ID_COLUMN) )
This DDL creates an unique index indexing -1 if the value of DEFAULT_COLUMN is 1234 and ID_COLUMN in any other case. Then, if two columns have DEFAULT_COLUMN value, it raises an exception.
The question implies to me that you have a primary table that has some child records and one of those child records will be the default record. Using address and a separate default table here is an example of how to make that happen using third normal form. Of course I don't know if it's valuable to answer something that is so old but it struck my fancy.
--drop table dev.defaultAddress;
--drop table dev.addresses;
--drop table dev.people;
CREATE TABLE [dev].[people](
[Id] [int] identity primary key,
name char(20)
)
GO
CREATE TABLE [dev].[Addresses](
id int identity primary key,
peopleId int foreign key references dev.people(id),
address varchar(100)
) ON [PRIMARY]
GO
CREATE TABLE [dev].[defaultAddress](
id int identity primary key,
peopleId int foreign key references dev.people(id),
addressesId int foreign key references dev.addresses(id))
go
create unique index defaultAddress on dev.defaultAddress (peopleId)
go
create unique index idx_addr_id_person on dev.addresses(peopleid,id);
go
ALTER TABLE dev.defaultAddress
ADD CONSTRAINT FK_Def_People_Address
FOREIGN KEY(peopleID, addressesID)
REFERENCES dev.Addresses(peopleId, id)
go
insert into dev.people (name)
select 'Bill' union
select 'John' union
select 'Harry'
insert into dev.Addresses (peopleid, address)
select 1, '123 someplace' union
select 1,'work place' union
select 2,'home address' union
select 3,'some address'
insert into dev.defaultaddress (peopleId, addressesid)
select 1,1 union
select 2,3
-- so two home addresses are default now
-- try adding another default address to Bill and you get an error
select * from dev.people
join dev.addresses on people.id = addresses.peopleid
left join dev.defaultAddress on defaultAddress.peopleid = people.id and defaultaddress.addressesid = addresses.id
insert into dev.defaultaddress (peopleId, addressesId)
select 1,2
GO
You could do it through an instead of trigger, or if you want it as a constraint create a constraint that references a function that checks for a row that has the default set to 1
EDIT oops, needs to be <=
Create table mytable(id1 int, defaultX bit not null default(0))
go
create Function dbo.fx_DefaultExists()
returns int as
Begin
Declare #Ret int
Set #ret = 0
Select #ret = count(1) from mytable
Where defaultX = 1
Return #ret
End
GO
Alter table mytable add
CONSTRAINT [CHK_DEFAULT_SET] CHECK
(([dbo].fx_DefaultExists()<=(1)))
GO
Insert into mytable (id1, defaultX) values (1,1)
Insert into mytable (id1, defaultX) values (2,1)
This is a fairly complex process that cannot be handled through a simple constraint.
We do this through a trigger. However before you write the trigger you need to be able to answer several things:
do we want to fail the insert if a default exists, change it to 0 instead of 1 or change the existing default to 0 and leave this one as 1?
what do we want to do if the default record is deleted and other non default records are still there? Do we make one the default, if so how do we determine which one?
You will also need to be very, very careful to make the trigger handle multiple row processing. For instance a client might decide that all of the records of a particular type should be the default. You wouldn't change a million records one at a time, so this trigger needs to be able to handle that. It also needs to handle that without looping or the use of a cursor (you really don't want the type of transaction discussed above to take hours locking up the table the whole time).
You also need a very extensive tesing scenario for this trigger before it goes live. You need to test:
adding a record with no default and it is the first record for that customer
adding a record with a default and it is the first record for that customer
adding a record with no default and it is the not the first record for that customer
adding a record with a default and it is the not the first record for that customer
Updating a record to have the default when no other record has it (assuming you don't require one record to always be set as the deafault)
Updating a record to remove the default
Deleting the record with the deafult
Deleting a record without the default
Performing a mass insert with multiple situations in the data including two records which both have isdefault set to 1 and all of the situations tested when running individual record inserts
Performing a mass update with multiple situations in the data including two records which both have isdefault set to 1 and all of the situations tested when running individual record updates
Performing a mass delete with multiple situations in the data including two records which both have isdefault set to 1 and all of the situations tested when running individual record deletes
#Andy Jones gave an answer above closest to mine, but bearing in mind the Rule of Three, I placed the logic directly in the stored proc that updates this table. This was my simple solution. If I need to update the table from elsewhere, I will move the logic to a trigger. The one default rule applies to each set of records specified by a FormID and a ConfigID:
ALTER proc [dbo].[cpForm_UpdateLinkedReport]
#reportLinkId int,
#defaultYN bit,
#linkName nvarchar(150)
as
if #defaultYN = 1
begin
declare #formId int, #configId int
select #formId = FormID, #configId = ConfigID from csReportLink where ReportLinkID = #reportLinkId
update csReportLink set DefaultYN = 0 where isnull(ConfigID, #configId) = #configId and FormID = #formId
end
update
csReportLink
set
DefaultYN = #defaultYN,
LinkName = #linkName
where
ReportLinkID = #reportLinkId