Describes a COMPUTED BY field.

       Format

         COMPUTED BY  value-expression

1  –  Argument

    value-expression

       Is a DEC DATATRIEVE value expression.

2  –  Examples

       In the following example, the price per pound of a yacht is
       computed as the price divided by the displacement. In this
       case, both the PRICE and DISP fields are defined in the record
       definition.

       06 PRICE_PER_POUND
          EDIT_STRING $$$,$$9.99
          COMPUTED BY PRICE/DISP.

       When the PRICE_PER_POUND field is used in a command or statement,
       DEC DATATRIEVE divides the value of the record's PRICE field by
       the value of its DISP field. The result of the computation is the
       value of the PRICE_PER_POUND field.

       In the following example, the discount price of a yacht is
       computed. The amount of the discount varies with the price of
       a yacht. The field PRICE is defined in the record definition for
       YACHTS:

       06 DISCOUNT_PRICE   COMPUTED BY
                 CHOICE
                    PRICE LT 20000 THEN (PRICE * .9)
                    PRICE LT 30000 THEN (PRICE * .8)
                    PRICE LT 40000 THEN (PRICE * .7)
                    ELSE (PRICE * .6)
                 END_CHOICE
                 EDIT_STRING IS $$$,$$$.

       When DISCOUNT_PRICE is used in a command or statement, DEC
       DATATRIEVE evaluates each Boolean expression in order until one
       evaluates to true. Then it performs the corresponding computation
       on PRICE.

       In the following example, the value of the SALESFORCE field is
       derived from a dictionary or domain table named SALES_TABLE:

       06 SALESFORCE
          EDIT_STRING IS X(20)
          COMPUTED BY MANUFACTURER VIA SALES_TABLE.

       In this example, DEC DATATRIEVE uses the value of the
       MANUFACTURER field in the current record to search the dictionary
       or domain table SALES_TABLE for a matching code. If one is
       found, DEC DATATRIEVE uses its translation as the value of the
       SALESFORCE field.