Defining a Table Validation Rule
The last detail to define is any validation rules that you want Microsoft Access to apply to any fields in the table. Although field validation rules get checked as you enter each new value, Access checks a table validation rule only when you save or add a row. Table validation rules are handy when the values in one field are dependent on what’s stored in another field. You need to wait until the entire row is about to be saved before checking one field against another.
One of the tables in the Contact Tracking database—Products—needs a table validation rule. Define that table now using the specifications in Table 4-7. Be sure to define ProductID as the primary key and then save the table and name it Products.