How To Modify a Table in Visual FoxPro Using Its Rules

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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.

1. Create a new DBC called "mydbc."
2. 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)
   						

3. Enter some records in the table.
4. 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
   						

5. Modify the table, and in the record validation rule type rec_valid().
6. In the field validation rule for custname, type fld_valid().
7. 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.