How to Create Validation Rules on Views

• Microsoft Visual FoxPro for Windows, versions 3.0 and 3.0b

SUMMARY

You can easily create field and row level validation rules for Visual FoxPro Tables by using the Table Designer. For local and remote views, however, the View Designers do not give you a way to visually create validation rules. For views, validation rules must be created programmatically by using dbsetprop().

MORE INFORMATION

Step-by-Step Example

1. Create an Updatable Local View:

   a. Open the TestData database in Samples\Data under the main Visual

         FoxPro directory.
   

   b. On the File menu, click New. Select View as the file type, and then

         click New File.
   

   c. Select EMPLOYEE from the Add Table or View list.

   d. In the Fields tab of the View Designer, click Add All to move all

         fields to selected output.
   

   e. In the Update Criteria tab, ensure that EMP_ID is marked as the key

         field and all other fields are marked as Updatable (they should have
         a check mark in the pencil column). click the Send SQL Updates
         button.
   

   f. Under the SQL WHERE clause options, select Key Fields only, and then

         save the view as EMP_VIEW.
   

2. Create a row-level Validation Rule to ensure that the Hire_date is later than the Birth_date:

   a. Type the following in the Command window:

         =dbSetProp("Emp_view","View","RuleExpression",;
             "Hire_date >Birth_date")
         =dbSetProp("Emp_view","View","RuleText",";
             'Hire date must be after birth date' ")
         USE Emp_view
         BROWSE
   
      b. Change the value of hire_date to be earlier than birth_date, and then
         move off the record. The validation rule fires and the error message
         is displayed.
   
   

3. Create a field level Validation Rule to ensure that the Last_name is not empty by typing the following in the Command window:

   =dbSetProp("emp_view.last_name","field","RuleExpression",;

         "not empty(last_name)")
   

   =dbSetProp("emp_view.last_name","field","RuleText",;

          " 'Last name cannot be blank' ")
   

   USE Emp_view BROWSE