The roots of the DBMS lie in file-based systems. The hierarchical and CODASYL systems represent the first-generation of DBMSs. The hierarchical model is typified by IMS (Information Management System) and the network or CODASYL model by IDS (Integrated Data Store), both developed in the mid-1960s. The relational model, proposed by E. F. Codd in 1970, represents the second-generation of DBMSs. It has had a fundamental effect on the DBMS community and there are now over one hundred relational DBMSs. The third-generation of DBMSs are represented by the Object-Relational DBMS and the Object-Oriented DBMS.