A tutorial introduction to data models in general is provided, with particular emphasis on the relational and network models defined by the two proposed ANSI (American National Standards Institute) database language standards. Examples based on the network and relational models include specific syntax and semantics, while examples from the other models are less precise. An example database is described and a discussion of the structures for modeling this database focuses on data types, actual structures, integrity constraints, and schema definition. An examination of data manipulation covers access from external languages and provides examples designed to show the power of the network and relational models in manipulating their data structures. Some characteristic features of the two models are then analyzed, including their specific benefits and limitations. A final chapter addresses additional issues in the selection of a database management system (DBMS), including access control, backup, recovery, bulk loading, and concurrency control. Most of the topics pertain to the daily operation of the DBMS itself rather than to the logical structures and operations of the data model. (LMM)