How to add null value to table field

Just add "NOT NULL" to all the columns you want to prevent from being NULL:

create table re(id numeric(1) NOT NULL,
bin varchar(10) NOT NULL)

      

        
        
        
      

    

If you want to change it later, you can do (syntax for SQL Server 2005 and above):

ALTER TABLE re
  ALTER COLUMN id NUMERIC(1) NOT NULL

ALTER TABLE re
  ALTER COLUMN bin VARCHAR(10) NOT NULL

      

        
        
        
      

    

What do you mean by "foreign key"? Which column? Which other table and column?

Check out some of these basic SQL tutorials first: they need to get started:

• Introduction to W3Schools Introduction
• SQL Tutorial

Mark