Creating a Select-list from Data (QSELECT)

QSELECT creates a select-list from the data in the specified file rather than from the item-IDs.

Format

QSELECT [DICT] filename {item-list | *} [(attr)]

Specify either an explicit item-list or all items in the file (with an asterisk). When specifying an item, the select-list will comprise all data in that item. Each line of data—that is, each attribute—of the item specified becomes a separate item-ID in the select-list. If specifying several items in the QSELECT statement, the select-list will comprise all of the data from all of the items specified, listed in the order of item-list.

The user may also specify that only data contained in a certain attribute be used in creating the select-list. attr is the number of the desired attribute (but cannot specify an attribute by its name).

The next example shows how a select-list may be used to reference a second file. Assume that Attribute 1 in the ORDERS file contains customer IDs. QSELECT creates a select-list of item-IDs from the data contained in Attribute 1. Then SORT-LABEL creates a mailing list from the CUSTOMERS file of these active customers to inform them of several new books that are available:

>QSELECT ORDERS * (1)

226 ITEMS SELECTED.

>SORT-LABEL CUSTOMERS BY LAST-NAME FULL-NAME STREET CITY-ST ZIP ID-SUPP

?3,5,1,13,15,5,C

?NAME

?ST

?CITY

?ZIP

If SELECT had been used instead of QSELECT in the preceding example, the select-list would contain item-IDs from the ORDERS file, which could not be used to access the CUSTOMERS file.