Question

I have a table where I need to change from “null” to “not null”.

I have a table with following structure:

Created_By   Created_Date_Time   Modified_By    Modified_Date_Time
NULL            NULL                -1                 NULL
NULL            NULL                -1                 NULL
NULL            NULL                -1                 NULL

I need to change Modified_By from -1 to null.

I am trying with the following query but it gives me an error:

update BOM_Rules
set Modified_By = not null

Error:

Cannot insert the value NULL into column 'Modified_By', table 'dbo.BOM_Rules'; column does not allow nulls. UPDATE fails.

I am sure I am missing something important. Maybe alter table?

ALTER TABLE BOM_Rules
ALTER COLUMN Modified_By NVARCHAR(50) NOT NULL

I am using SQL2008R2.

Answer 1

It sounds like the Modified_By column does not allow nulls. Try altering the column to allow nulls:

ALTER TABLE BOM_Rules
ALTER COLUMN Modified_By NVARCHAR(50) NULL