A rule lets you specify what users can or cannot enter into a particular column or any column with a user-defined datatype. In general, to create a rule you:
Create the rule using create rule.
Bind the rule to a column or user-defined datatype using sp_bindrule.
Test the bound rule by inserting data. Many errors in creating and binding rules can be caught only by testing with an insert or update command.
You can unbind a rule from the column or datatype either by using sp_unbindrule or by binding a new rule to the column or datatype.
