2 Acknowledgements I would like to thank my supervisor Patrick Browne for his help and support with this project. A special thank you to my family without whose support and encouragement this endeavour would not have been possible. Abstract The theme of this report is the development of two graphical clients using the Java programming language. The first supports the native geometric data types of the PostgreSQL Database Management System (DBMS), the second supports the spatial objects of PostGIS, the spatial extension for PostgreSQL. The clients issue SQL commands to a DBMS using the proprietary JDBC extensions that support the spatial data types and the resulting data is displayed graphically. The clients also allow the user to issue ad hoc SQL commands to the DBMS. An existing Java toolkit called OpenMap, which is a set of Java Swing components that understand geographic coordinates, was extended. This provided the framework for the client development. In both cases a layer was created capable of converting the database types into the graphic objects required by the OpenMap framework. The concepts of spatial databases and Geographic Information Systems (GIS) are introduced and discussed. Existing standards for SQL and GIS are discussed. The feasibility of the use of PostgreSQL/PostGIS as the backend spatial database of a GIS is examined.