File management method using transposed file

Abstract

A file management system performs flexible and efficient file management with a transposed file. First, variable-length logical fields constituting the records in an original file are converted to variable-length internal fields with field-to-field correspondence being maintained and fields aligned with word boundaries. Next, the records consisting of internal fields are divided into multiple record groups which may comprise a variable number of records. For each record group, one or a plurality of internal fields of all records are then sorted into blocks and blocks are set in a row as a group. Groups thus generated from all records are assembled into a transposed file. When requested to retrieve field data from the original file, the file management system accesses the transposed file and reads only blocks comprising target field data.