SPARSE ARRAY BIT MAP USED IN DATA BASES

A data base system uses a self-descriptive index key format having variable length data fields so that the data base system manipulation is independent of the type and arrangement of the data being stored and retrieved. The data is characterized by three index variables which represent the data table, the record in that table, and a particular field within that record. Each table is composed of data imbedded in the B-tree index structure of the data base. In order to access records using the field variables, the data base additionally includes an inverted B-tree index logically related to the original index. The operation of the index is enhanced by the use of data compression and the use of a sparse array bit map to represent the record associated with each field. The index structure within the data base allows each index variable to identify data by means of the index variables independently of the physical location in which the data is stored. The efficiency of storage is further enhanced by storing the data in variable length data records. The sparse array bit maps also be used to provide interrecord relationships for records stored in different data tables.