The currently operational version of the INGRES data base management system gives a relational view of data, supports two high level, non-procedural data sublanguages, and runs as a collection of user processes on top of a UNIX operating system. The authors stress the design decisions and tradeoffs in relation to (1) structuring the system into processes, (2) embedding one command language in a general purpose programing language, (3) the algorithms implemented to process in interactions, (4) the access methods implemented, (5) the concurrency and recovery control provided, (6) support for views, protection and integrity constraints, and (7) the data structures used for system catalogs and role of the data base administrator. (Author/CH)