HOWTO: Modify a Table in Visual FoxPro Using Its Rules

ID: Q158255

The information in this article applies to:

Microsoft Visual FoxPro for Windows, versions 5.0, 6.0

SUMMARY

In Visual FoxPro 5.0 or later, the field validation rules and the record validation rules can now modify the table to which they belong. This is not possible in Visual FoxPro 3.0.

MORE INFORMATION

For example, suppose you want to track when each update was made to a record, check a maximum order amount, and capitalize entries in a certain field. The following steps illustrate how this might be done.

Create a new DBC called "mydbc."

Issue the following command to create a table:


      CREATE TABLE cust(custname c(10),chg_date D, order N(5), ;
      max N(5), limit L)

Enter some records in the table.

Enter the following in the stored procedures:


      PROCEDURE rec_valid
         REPLACE chg_date WITH DATE()
         IF order > max
            REPLACE limit With .t.
         ELSE
            REPLACE limit with .f.
         ENDIF
      ENDPROC

      PROCEDURE fld_valid
        IF !EMPTY(ALLTRIM(custname)) AND ;
           ALLTRIM(PROPER(custname))<>ALLTRIM(custname)
            REPLACE custname WITH PROPER(custname)
        ENDIF
      ENDPROC

Modify the table, and in the record validation rule type rec_valid().

In the field validation rule for custname, type fld_valid().

Browse the table, add new records, and edit existing records.

Notice the chg_date is modified for each new record and for any existing record that is edited. The limit field is set to true each time the order field exceeds the max field. The first letter of custname is always capitalized regardless of how the name is entered or changed.

Additional query words:

Keywords : kbDatabase kbVFp500 kbVFp600 KbDBFDBC
Version : WINDOWS:5.0,6.0
Platform : WINDOWS
Issue type : kbhowto