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Get to know about the relational data- and object model used in {{UBIK}} beginning from a rather figurative and abstract point of view. We will introduce the essential parts of the object model and show how these items are connected to a real system. ==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
* manage process or maintenance data of the plant and its features
* do a high-performance cost-benefit analysis and create key performance indicators
Therefore we need to
</strong>
==From the plant picture to {{UBIK}}=====Transition===[[File:IL_DOM_003.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|A descriptive model, where objects provide information about the aspects of the data, is also called “Metamodel”.}} So far we have identified <strong>{{check_mark}} Theoretical blocks representing the parts of the system {{check_mark}} Necessary properties of these blocks</fontstrong> An important aspect of the datamodel has not been discussed yet, namely <b>how are the blocks (=[[MetaClass|MetaClasses]]) related to each other?</divb> == Relating objects ==[[File:IL_DOM_004.png|thumb|220px|alt=Relations of plant parts|Possible relations between parts of plant]]Assuming that all three pumps are clearly parts of the plant „UBIK1“, the descriptive model has to be extended in order to include this information as well. In our "table" view we account for this by adding a property to the ''PUMP'' block refering to the plant. This additional property represents the link information between the pumps #1 - #3 and the plant „UBIK1“. <table><tr><td>[[File:IL_DOM_005.png|400 px|alt="Relation pump and plant"]]</td><td> [[File:IC_ArrowGreenRight.png|20 px]] </td><td>{| class="wikitable"|-! Pump !! TAG !! Vendor !! Power !! Maintenance !! Plant|- align="center"| #1 || style="width: 80px;" | P0815 || style="width: 100px;" | Andritz || style="width: 50px;" align="right" | 2 kW || Yearly || style="width: 80px; background-color: #C3D69B" | UBIK1|- align="center"| #2 || P0816 || Andritz || align="right" | 5 kW || Monthly || style="background-color: #C3D69B" | UBIK1|- align="center"| #3 || P0817 || Sulzer || align="right" | 4 kW || Yearly || style="background-color: #C3D69B" | UBIK1|}</td></tr></table> {{UMM|Add a metaproperty „Plant“ to the MetaClass „Pump“, where the values of the MetaProperty refer to the plant „UBIK1“.}} Now we introduce two armatures with the properties from the descriptive model above. Assume that, due to the piping, pumps #1 and #2 are controlled by both armatures, whereas A200 regulates pump #3 only. This situation is depicted below already indicating, that the implementation of the relation requires a more complex structure. We find three pumps on the left side and two armatures on the right side of the relation, respectively. Managing this control relation in the Metamodel requires to introduce a relation block ''CONTROL'' with two MetaProperties „Armature#“ and „Pump#“ <table><tr><td>[[File:IL_DOM_006.png|400 px]]</td><td>[[File:IC_ArrowGreenRight.png|20 px]]</td><td>{| class="wikitable"|-! Armature# !! Pump# |- align="center"| A100 || style="width: 80px;" | P0815 |- align="center"| A100 || P0816 |- align="center"| A200 || P0815|- align="center"| A200 || P0816|- align="center"| A200 || P0817 |}</td><td>[[File:IC_ArrowGreenRight.png|20 px]]</td><td>[[File:UDOM_Relating3.png|150 px]]</td></tr></table> {{UMM|Managing the control relation in the Metamodel requires to introduce a relation block „CONTROL“ with two MetaProperties „Armature#“ and „Pump#“.}} Lets have a closer look at the characteristics of the two methods relating objects:<table><tr><td align="center" valign="top">{| class="wikitable"|-! Pump !! TAG !! Vendor !! Power !! Maintenance !! Plant|- align="center"| #1 || style="width: 80px;" | P0815 || style="width: 100px;" | Andritz || style="width: 50px;" align="right" | 2 kW || Yearly || style="width: 80px; background-color: #C3D69B" | UBIK1|- align="center"| #2 || P0816 || Andritz || align="right" | 5 kW || Monthly || style="background-color: #C3D69B" | UBIK1|- align="center"| #3 || P0817 || Sulzer || align="right" | 4 kW || Yearly || style="background-color: #C3D69B" | UBIK1|}</td><td align="center">{| class="wikitable"|-! Armature# !! Pump# |- align="center"| A100 || style="width: 80px;" | P0815 |- align="center"| A100 || P0816 |- align="center"| A200 || P0815|- align="center"| A200 || P0816|- align="center"| A200 || P0817 |}</td></tr><tr><td align="center">[[File:IC_ArrowGreenDown.png|40 px]]</td><td align="center">[[File:IC_ArrowGreenDown.png|40 px]]</td></tr><tr><td align="center"><i>each</i> pump refers exactely to the <i>one</i> plant</td><td align="center"><i>two</i> pumps are controlled by <i>two</i> armatures<br><i>one</i> pump is controlled by <i>one</i> armature</td></tr><tr><td align="center">[[File:IC_ArrowGreenDown.png|40 px]]</td><td align="center">[[File:IC_ArrowGreenDown.png|40 px]]</td></tr><tr><td align="center"><b>Cardinality 1 : n</b></td><td align="center"><b>Cardinality n : n</b></td></tr></table> {{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:IL_DOM_007.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:IL_DOM_009.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. {{UMM|* <b>1 : n</b> relationships are called <b>“References”</b> (one pump refers to exactly one plant)* <b>n : n</b> relationships are called <b>“Relations”</b> (two pumps are controlled by two armatures, one pump is controlled by one armature)}} Congratulations, we integrated another important issue in our data- and object model: {{check_mark}} <b>Relationships between blocks (MetaClasses)</b> ==MetaClasses and Instances==So far MetaClasses define the structure of and possible relations between the objects in our data model. In the next step it will be shown how to create actual objects of these blueprints and how to deal with it. === Instances ===[[File:IL_DOM_008.png|thumb|220 px|alt=UBIK Instance model|{{UBIK}} Instance Model]]Populating our data modell with real data from a plant means, that we create objects as defined by the MetaClasses. These objects are called instances, and leads us to the next definition.{{UMM|An '''instance''' is the actual „existing“ occurrence of the described object (within the metamodel). The instances can be differentiated by their property values.}}=== MetaClass & MetaProperties ===[[File:IL_DOM_012.png|thumb|220 px|alt=Relation MetaClass / MetaProperty|Relation MetaClass / MetaProperty]][[File:IL_DOM_010.png|thumb|220 px|alt=Usage MetaClass / MetaProperty|Usage MetaClass / MetaProperty]]In the similar way as MetaClasses are related to each other, MetaProperties are related to MetaClasses. Hence, we obviously find that* a MetaProperty can be related to multiple MetaClasses* be used multiple times for defining a MetaClass' structure{{UMM|MetaProperties are assigned to a MetaClasses via relations}} === MetaClass & Inheritance ===[[File:IL_DOM_013.png|thumb|220 px|alt=Inheritance MetaClass|Inheritance MetaClass]]We can build up a hierarchical tree of MetaClasses, where MetaClasses inherit properties.<table><tr><td></td><td></td><td align="center" valign="top">{| class="wikitable"|-! Pump !! TAG !! Vendor !! Power !! Maintenance !! Plant|- align="center"| #1 || style="width: 80px;" | P0815 || style="width: 100px;" | Andritz || style="width: 50px;" align="right" | 2 kW || Yearly || style="width: 80px; background-color: #C3D69B" | UBIK1|- align="center"| #2 || P0816 || Andritz || align="right" | 5 kW || Monthly || style="background-color: #C3D69B" | UBIK1|- align="center"| #3 || P0817 || Sulzer || align="right" | 4 kW || Yearly || style="background-color: #C3D69B" | UBIK1|}</td></tr><tr><td></td><td></td><td align="center">[[File:IC_ArrowGreenDown.png|40 px]]</td></tr><tr><td align="center" valign="top">{| class="wikitable"|-! Piston pump !! Stroke freq. |- align="center"| #1 || style="width: 80px; background-color: #C3D69B" | 1 / s|- align="center"| #2 || style="width: 80px; background-color: #C3D69B" | 0,1 / s|}</td><td align="center">[[File:IC_ArrowGreenRight.png|40 px]]</td><td align="center" valign="top">{| class="wikitable"|-! Pump !! TAG !! Vendor !! Power !! Maintenance !! Plant!! Stroke freq. |- align="center"| #1 || style="width: 80px;" | P0815 || style="width: 100px;" | Andritz || style="width: 50px;" align="right" | 2 kW || Yearly || UBIK1|| style="width: 80px; background-color: #C3D69B" | 1 / s|- align="center"| #2 || P0816 || Andritz || align="right" | 5 kW || Monthly || UBIK1 || style="width: 80px; background-color: #C3D69B" | 0,1 / s|}</td></tr></table>{{UMM|MetaClasses pass on MetaProperties to child-MetaClasses („Inheritance“)}} === MetaClass & Classification ===[[File:IL_DOM_011.png|thumb|220 px|alt=Classification|Classification]]MetaClasses can specify features and properties of other MetaClasses by using a "Classification" technique. The result can be described by* "A piston pump is a pump and an element of the fluid technology." [gen]* "Piston pump" is a child MetaClass of „Pump“ and classified as "Fluid technology" object. [techn.]{{UMM|MetaClasses can specify features of other MetaClasses ("Classification")}} === MetaProperties ===Each MetaProperty can be specified by its own attributes which are well-known from other systems.<table><tr><td>{| class="wikitable"|-! MetaProperty|- align="center"| "Name"|- align="center"| "Year"|- align="center"| "Location" |- align="center"| "TAG"|- align="center"| "Plant"|- align="center"| "Power"|}</td><td>{| class="wikitable"|-! Name !! Description !! Data type !! Unit !! Format !! Length !! ...|- align="center"| "Name"|| Name of object || String || - || - || 20 || ...|- align="center"| "Year" || Year of construction || Numeric || - || #### || - || ...|- align="center"| "Location" || Plant location || String || - || - || 200 || ...|- align="center"| "TAG" || TAG number || String || - || - || - || ...|- align="center"| "Plant" || Reference to plant || Reference || - || - || - || ...|- align="center"| "Power" || Power || Numeric || kW || ###.## || - || ...|}</td></tr></table>{{UMM|MetaProperties have specific attributes, closely related to the intended property value}} ==Conclusion==* The descriptive model consists of '''MetaClasses''' and '''MetaProperties''' and relations between these objects.* Each MetaClass is defined by** a collection of MetaProperties** the line of inheritance** classification information * A MetaProperty implements different features and settings.* In this MetaModel we explicitely distinguish between the description (structure, relations,…) and '''instances''' (actual occurences) of data objects* The MetaClasses might be on an equal hierarchy level from the descriptive point of view, whereas the instances are then related using '''references''' and '''relations''' [[Category:UBIK|Entity Data Model]]
