==Introduction=====Objectives===
In an industrial environment we quite often need to
* describe an industrial plant consisting of a bunch of different parts, each having a certain purpose and set of properties, and which are related in various ways
{{ToDo}} Think about the functions and features of blocks.
===Plant picture===
[[File:UDOM_PlantParts.png|thumb|220px|alt=Parts of a plant|Example plant and parts]]
Lets start with a simple picture and assume that our plant consists of a pump and an armature. Both equipments exhibit certain technical or other properties, which our datamodel must contain in some form. Additionally the datamodel has to provide mechanism to indicate the circumstances that both equipments are parts of the plant and maybe even be related to each other.
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==From the plant picture to {{UBIK}}=====Transition===
[[File:UDOM_TransitionMetaModel.png|thumb|220px|alt=Transition plant picture|Transition from plant picture into data model]]
The transition from the plant picture into an object- / data - model logically happens via an intermediate layer and finally leads to our first definition
{{UMM|Data model built and described by MetaClasses and MetaProperties related to each other, either by <b>1 : n</b> or <b>n : n</b> cardinality.}}
===Entity Relationship Model (ER model)===
[[File:UDOM_Relating4.png|thumb|220 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 entity-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===
[[File:UDOM_Relating5_RefRel.png|thumb|220 px|alt=References and Relations|{{UBIK}} References and Relations]]
Concluding and summarizing the above discussion we finally depict the two possible types of relation in the {{UBIK}} MetaModel.
{{Checked}} <b>Relationships between blocks (MetaClasses)</b>
==Conclusion==