A relative record file contains records ordered by their relative key, that is, a record number that represents the location of the record relative to where the file begins.
For example, the first record in a file has a relative record number of 1, the tenth record has a relative record number of 10, and so forth. The records can have fixed length or variable length.
The record transmission modes allowed for relative files are sequential, random, or dynamic. When relative files are read or written sequentially, the sequence is that of the relative record number.
related references
Valid COBOL statements for indexed and relative files