Join Logical Files

Join files are a special kind of logical file you can use to combine, in a single record, the fields contained in two or more records (in files elsewhere). Join files have the following limitations:

• You cannot open a join file for update or output. You can only open a join file for input. In other words, you can only read a join file. A join file can contain only one record format, as opposed to nonjoin logicals, which can contain many record formats.

• You can join two records only if the joining fields have the same type length and have equal values. If you define key fields for a join file, all key fields that make up the key must come from the first file listed in the JFILE keyword (see below).