SQL Server Error Messages - Msg 8101¶

Error Message¶

Server: Msg 8101, Level 16, State 1, Line 2
An explicit value for the identity column in table "Table Name" can only be specified when a column list is used and IDENTITY_INSERT is ON.

Causes¶

This error happens when you are trying to insert a new record into a table that contains an identity column without specifying the columns in the INSERT statement and you are assigning a value to the identity column instead of letting SQL Server assign the value.

To illustrate on how the error can be encountered:

CREATE TABLE [dbo].[Users] (
    [UserID]    INT NOT NULL IDENTITY(1, 1),
    [UserName]  VARCHAR(20) NOT NULL,
    [FirstName] VARCHAR(50) NOT NULL,
    [LastName]  VARCHAR(50) NOT NULL
)
GO

INSERT INTO [dbo].[Users] 
VALUES ( 1, 'superman', 'Clark', 'Kent' )
GO

Msg 8101, Level 16, State 1, Line 2
An explicit value for the identity column in table 'dbo.Users' can only be specified when a column list is used and IDENTITY_INSERT is ON.

If you specified the column names in the INSERT statement, you will get a different error message:

INSERT INTO [dbo].[Users] ( [UserID], [UserName], [FirstName], [LastName] )
VALUES ( 1, 'superman', 'Clark', 'Kent' )
GO

Msg 544, Level 16, State 1, Line 2
Cannot insert explicit value for identity column in table 'Users' when IDENTITY_INSERT is set to OFF.

Solution / Workaround¶

There are two ways of avoiding any of the errors mentioned above. The first option is not to include the identity column in the INSERT statement and let SQL Server assign the next identity value to the record:

INSERT INTO [dbo].[Users] ( [UserName], [FirstName], [LastName] )
VALUES ( 'superman', 'Clark', 'Kent' )
GO

The second option is to enable the IDENTITY_INSERT property for the table. If you really want to specify the value for the identity column, this option is the one for you.

SET IDENTITY_INSERT [dbo].[Users] ON
GO

INSERT INTO [dbo].[Users] ( [UserID], [UserName], [FirstName], [LastName] )
VALUES ( 1, 'superman', 'Clark', 'Kent' )
GO

SET IDENTITY_INSERT [dbo].[Users] OFF
GO

Setting the IDENTITY_INSERT to ON for the table allows explicit values to be inserted into the identity column of a table. At any given time, only one table in a session can have the IDENTITY_INSERT property set to ON. If a table already has this property set to ON and a SET IDENTITY_INSERT ON statement is issued on another table, SQL Server will return the following error message:

Msg 8107, Level 16, State 1, Line 2
IDENTITY_INSERT is already ON for table 'dbo.Deparments'. 
Cannot perform SET operation for table 'dbo.Users'.

Execute permissions for the SET IDENTITY_INSERT default to the sysadmin fixed server role and the db_owner and db_ddladmin fixed database roles, and the object owner.