title: Update script for updating a table field in SQL Server from NULL to non-NULL
body: <p>I have a field (say, foo) in a table in a SQL Server database that was originally defined as nullable, but new requirements indicate that this field must be non-null.</p>
  
  <p>What's the best way of updating this field to non-null via an update script without deleting the contents of the table?  I tried generating a script from the Design view, but fails during execution because the current contents of the table had NULL values for foo.  Worse yet, if I ignored this error, it proceeds to delete all the contents of the table!</p>