| Navigation: User's Guide and Tutorials > Getting Started with Clarion! >====== Exercise Six - Set the Lookup Validity Check ====== |    |
Now that the table relationship is defined, we can set the Validity Checks for the column that we expect to use on update forms.
When entering a new Customer, we can specify that the State column must match an existing record in the States table.
Define the Validity Check for the Customer State column
1.Highlight the Customer table in the DCT Explorer list.
2.In the Fields Quick View list, highlight the State column entry and press the Change button 
located in the Fields list toolbar.
This opens the Entity Browser and Properties for the Customer table.
3.Select the Validity Checks tab.
4.Select the Must Be In Table radio button.
5.Choose States from the Table Label dropdown list.
This requires that the column can only contain values verified by getting a matching row from the States table. This is validated using the table relationship information, which is why this Validity Check cannot be set until the relationships have been defined.
6.Press the Save and Close button 
to close the Customer table.