===Entity Relationship Model (ER model)===
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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.
[[File:UDOM_Relation4.jpg]]