The ORDERS file implements MultiValued attributes to describe the data in a single order transaction. When a customer places an order, the data is stored in an item in the ORDERS file. Each book is identified by a unique product code. For example, when displayed by the LIST-ITEM command, item 10118 in the ORDERS file has the following structure:
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>LIST-ITEM ORDERS '10118' 10118 001 DROBI5424 002 7563 003 N01]QR02]N04 004 3]2]1 005 CASH 006 UPS |
Attribute 3 contains the code numbers of the ordered books and Attribute 4 contains the number of books ordered. Attributes 1, 2, 5, and 6 each have only a single value. The rest of the data that describes an order transaction (such as PRICE, TITLE, AMOUNT, and TAX) are derived from existing data. Value marks (entered in the file with the CTRL+] key sequence) separate the pieces of data in each MultiValued attribute.
The data in item 10118 can be interpreted as follows:
3 copies of book N01.
2 copies of book QR02.
1 copy of book N04.
See Also