AbstractA relational database (RDB) has been developed for classifying TJ-II experimental data according to physical criteria. Two objectives have been achieved: the design and the implementation of the database and the software tools for data access depending on a single software driver. TJ-II data were arranged in several tables with a flexible design, speedy performance, efficient search capacity and adaptability to meet present and future, requirements. The software has been developed to allow the access to the TJ-II RDB from a variety of computer platforms (alpha axp/True64 unix, cray/unicos, Intel Linux, Sparc/Solaris and Intel/Windows 95/98/NT) and programming languages (fortran and c/c++). The database resides in a Windows NT Server computer and is managed by Microsoft SQL Server. The access software is based on open network computing remote procedure call and follows client/server model. A server program running in the Windows NT computer controls data access. Operations on the database (through a local ODBC connection) are performed according to predefined permission protocols. A client library providing a set of basic functions for data integration and retrieval has been built in both static and dynamic link versions. The dynamic version is essential in accessing RDB data from 4GL environments (IDL and PV-WAVE among others).