Cannot change column to Not Null: Cannot insert the value NULL into column '', table '.dbo.Tmp_'; column does not allow nulls.

Introduction

In sql server 2008/ 2005, when you are modify column in table the from null column to non null column, you will get this error

'<TableName>' table
- Unable to modify table. 
Cannot insert the value NULL into column '<ColumnName>', table 'Database.dbo.Tmp_<TableName>'; column does not allow nulls. INSERT fails.
The statement has been terminated.
 

This is occurs if there is already data in this table and this column contains nulls.

Solution

If this column int type, then you can set the - 1 to that column, then it does not null. If char type column then you can set empty values as well. for update you can use the T-SQL.

thank you for reading.