Binding a rule to a user-defined datatype

Select the User-defined Datatypes folder for the database in which you are working.
Select the user-defined datatype to which you want to bind a rule, then choose File | Properties.
Select the Advanced Options tab.
Select a rule from the Rule list.
Optionally, select In Future Only. If you select In Future Only, the rule is applied only to columns of this type added to a table after you bind the rule. It does not apply to columns of this type currently in a table. If you do not select In Future Only, the rule is applied to columns of this type currently in tables and columns of this type added later.