SQL Server Error Messages - Msg 1753

Error Message

Server: Msg 1753, Level 15, State 1, Line 1
Column 'Table.Primary Key' is not the same length as referencing column 'Referencing Table.Referencing Column' in foreign key 'Foreign Key Constraint Name'.

Causes:

This error occurs when you are trying to create a foreign key relationship between two tables and the length of the referencing column is different from the length of the primary key.

To illustrate, here’s a script that will generate the error:

CREATE TABLE [dbo].[Employees] (
    [ID]    VARCHAR(10) PRIMARY KEY,
    [Name]  VARCHAR(50),
    [Position]    VARCHAR(2)
)
GO

CREATE TABLE [dbo].[EmployeeManager] (
    [ManagerID]  VARCHAR(5) REFERENCES [dbo].[Employees] ( [ID] ),
    [EmployeeID] VARCHAR(5) REFERENCES [dbo].[Employees] ( [ID] )
)
GO

Executing this script will generate the following error:

Server: Msg 1753, Level 16, State 1, Line 6
Column 'dbo.Employees.ID' is not the same length as referencing column 'EmployeeManager.ManagerID' in foreign key 'FK__EmployeeM__Manag__2BFE89A6'.
Server: Msg 1750, Level 16, State 1, Line 6
Could not create constraint. See previous errors.

Solution / Work Around:

To avoid this error, always make sure that the length of the referencing column is the same as the length of the primary key being referenced. The following script will solve the problem:

CREATE TABLE [dbo].[Employees] (
    [ID]        VARCHAR(10) PRIMARY KEY,
    [Name]      VARCHAR(50),
    [Position]  VARCHAR(2)
)
GO

CREATE TABLE [dbo].[EmployeeManager] (
    [ManagerID]  VARCHAR(10) REFERENCES [dbo].[Employees] ( [ID] ),
    [EmployeeID] VARCHAR(10) REFERENCES [dbo].[Employees] ( [ID] )
)
GO