Network database access system to which builds a table tree in response

Abstract

The database access system of the present invention accesses a hierarchical network type database, treating it as a relational type database. The system analyzes queries in data manipulation language for a relational database which define instructions for retrieval, update, addition and deletion conditions using query analyzing means. According to the analysis result, a record relation tree of the relation among records having the individual fields related to the operation conditions is generated by record relation combining means and stored in storing means. Further, operation conditions are resolved into sets of binary operations using retrieval, update, addition or deletion condition analyzing means so as to generate a condition tree having the operators used in the binary operations as nodes. The access module generating means generates access modules for access to a hierarchical database file based on the record relation tree and condition tree and the access executing means executes accessing based on these access modules.