After a brief survey of existing database management systems (DBMS) for small machines the authors describe the design and implementation of a microcomputer-based DBMS intended for the non-specialist user. Portability, interactivity, and simplicity requirements led to the choice of [1] the relational database model, (2) a non procedural query language (query by example) and (3) a structured programming language (Pascal). The data structures and techniques used in implementation are presented. The authors analyze the general performance of the system. Finally, they discuss three specific factors: the portability, orthogonality and integrity of the system