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/* Entity Relationship Model (ER model) */
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[[File:UDOM_Relating4.png|thumb|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. The metaclass ''„CONTROL“ '' can be drawn as diamond, signalling the additional block between these two metaclasses, which is always needed for each relation of cardinality n : n.
===About References and Relations===
