It is expected that future data base management systems will include a component for handling conceptual schemata. This Report explains the roles and concepts for a conceptual schema with the intention of providing a framework for discussion and for the design of conceptual schema languages. The rules described in the conceptual schema control to a large extent what may or may not happen in an information system and a data base. Therefore their Report is not limiting its attention to the conceptual schema alone@ but also considers basic concepts for the mechanisms involved in manipulating a conceptual schema and a data base. This Report is aimed at designers of information systems and data bases as well are suppliers of conceptual schema facilities. The provided framework will prepare the way for eventual standardization in the area of data base management. It does not@ however@ describe any particular method for using such facilities. In the meantime@ the general principle8 in this Report can be used to evaluate emerging DBMS facilities. The approaches and associated languages described in appendices to the Report are intended to be explanatory only and are not ipso facto candidates for a standard conceptual schema language.