The primary purpose of the multipart standard ISO/IEC 19763 is to specify a metamodel framework for interoperability. This part of ISO/IEC 19763 specifies a metamodel for registering information models. This metamodel was developed taking into account two distinct types of information models such as — those that are used to document the information requirements of a particular area of interest, and — those that represent the structure of a database which are often expressed using a Database Definition Language (DDL). Information models that represent information requirements can be developed using a number of different common diagramming techniques and notations. The metamodel specified in this part of ISO/IEC 19763 was developed to cover the registration of models expressed using the following techniques and notations: — Express-G, an ISO standard entity-relationship modelling notation, as described in Reference [8]; — IDEF1X, a US Federal standard entity-relationship modelling notation, as described in References [6] and [12]; — the entity-relationship modelling notation first developed by Harry Ellis and Richard Barker and later adopted by Oracle for its CASE*Method and by the UK's CCTA for SSADM (Structured Systems Analysis and Design Method), as described in Reference [2]; — the UML Class Diagram notation, as described in References [13] and [14]; — the original entity-relationship modelling notation proposed by Peter Chen, as described in Reference [4]; — the Information Engineering entity-relationship modelling notation, as described in Reference [11]. It is understood that these selected techniques represent all of the essential features of all information modelling techniques used to represent information requirements. The registration of information models that represent the structure of a database is limited in the metamodel specified in this part of ISO/IEC 19763 to those database structures that conform to the Core SQL specification. Core SQL is the set of features defined in the conformance requirements specified in ISO/IEC 9075-2 and ISO/IEC 9075-11. The registration of information models that are expressed using notations such as Object Role Modeling (ORM) and "Natural language Information Analysis Method" (NIAM), collectively known as fact-based models, is out of scope for this part of ISO/IEC 19763.