[en] The paper describes the structure of an atomic database for application to impurity problems in fusion plasmas. It is designed for interactive computer use by both specialists in atomic physics and those concerned with plasma interpretation and diagnostics. Thus it contains data entry as well as data extraction and manipulation procedures. The detailed description of the methodology and its basis in atomic physics is described in sections 1 and 2. Section 3 and appendix C describes the practical implementation, and in particular its operation from the JET IBM SPF panel system. Section 4 is a technical discussion of data sources. (author)