===Entity Relationship Model (ER model)===
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[[File:UDOM_Relating4.png|thumb|600 400 px|alt=ER-model|Entitiy-Relationship-Model]]
In software engineering, such an abstract descriptive model is called Entity–Relationship model (ER model) and describes the entities (=UBIK® metaclasses) and relationships between them. Usually this information is depicted in an entitiy-relationship-diagram (ERD), which draws the corresponding data objects and relations as rectangles and lines between them, respectively.