When only certain records from an input file are needed for an application, MFX allows you to set up one or more logical conditions for including only those records. Alternately, you may specify conditions for omitting records from an application. Each condition is based on a comparison between two record fields or between a record field and a constant. You may specify the constant as a positive or negative decimal, a hexadecimal or binary constant, or a character literal. Multiple conditions may be specified, provided you connect them with ANDs and ORs.
To specify the conditions for selecting records, use the INCLUDE/OMIT control statement. For complete syntax, and examples of bit level criteria in record selection, see INCLUDE/OMIT Control Statement.
When processing variable-length records, by default all fields specified must be contained within the record. If an application is expected to reference fields not completely contained within the record, see VLTESTI. VLTESTI provides for processing of records that do not contain all fields.