The Conceptual Domain Model contains the identification and description of the entities of the domain and the relationships between them.
At this stage of the project we are mainly interested in the database specification, thus the Conceptual Domain Model is simplified to include only concepts (entities and relationships) of the domain that are stored in the database. In this artefact the data requirements of the system are detailed.
The Conceptual Data Model is obtained by using a UML class diagram containing the classes, associations, multiplicity and roles. For each class, the attributes, associations and constraints are included in the class diagram. Business rules not included in the class diagram are described by words or using OCL (Object Constraint Language) included as UML notes.