HowTo:Relate Objects - Revision history

NWE at 18:00, 29 January 2020

2020-01-29T18:00:20Z

NWE at 17:58, 29 January 2020

2020-01-29T17:58:42Z

NWE at 09:30, 5 December 2019

2019-12-05T09:30:55Z

CRO at 09:06, 5 December 2019

2019-12-05T09:06:27Z

NWE at 18:57, 3 December 2019

2019-12-03T18:57:42Z

NWE: /* Connect objects via Reference */

2019-12-03T18:35:00Z

‎Connect objects via Reference

NWE at 18:34, 3 December 2019

2019-12-03T18:34:48Z

NWE at 18:34, 3 December 2019

2019-12-03T18:34:30Z

KNO at 16:16, 30 July 2015

2015-07-30T16:16:15Z

KNO: Created page with "Relating objects is one of the essential parts within {{UBIK}} and can be achieved by two means: * Use Relations to build up an n:n relationship between two insta..."

2015-07-30T16:15:50Z

Created page with "Relating objects is one of the essential parts within {{UBIK}} and can be achieved by two means: * Use Relations to build up an n:n relationship between two insta..."

New page

Relating objects is one of the essential parts within {{UBIK}} and can be achieved by two means:
* Use [[Relation|Relations]] to build up an n:n relationship between two instances of an entity
* Use [[Reference|References]] to build up an 1:n relationship between two instances of an entity

Which method fits best can not be predicted and clearly depends on the use case and the data model.

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 * An instance "objectA" of that meta class
 * An instance "objectB" of the reference target meta class
 <source lang="csharp">
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 </source>
 Similarly, you can also read a connected object:
 <source lang="csharp">
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 * An instance "objectA" of the relation's left target meta class
 * An instance "objectB" of the relation's right target meta class
 <source lang="csharp">
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 </source>
 You can also read relational information in multiple ways (assuming objectA is already declared as variable of type RelationalObject to avoid the casts):
 <source lang="csharp">

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 ## Open '''A''' in the Relation Editor. In the tree view you see now, drag '''B''' onto the tree node for the previously created relation.
 # Save all changes. The connection is now established and can be used, e.g., in the ACM view or by programmatic customizing.
 [[Category:How-To|Relate Objects]]

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 == Connect objects via Reference ==
-If you want one or multiple objects to refer to a single target object each, a [[Reference]] is what you need. You can either ask an object about the one it refers to, or ask a target object about all objects referring to it via a reference. This is useful, if you want to connect objects but there is no necessity for '''both''' "sides" to be connected to multiple other objects.
+If you want an object to refer to a single target object (1:n relation), a [[Reference]] is what you need. You can either ask an object about the one it refers to, or ask a target object about all objects referring to it via a reference. This is useful, if you want to connect objects but there is no necessity for '''both''' "sides" to be connected to multiple other objects.
 In this case, an object's property contains a link to the target object (respectively, its UID).
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 == Connect objects via Relation ==
-If you want to connect one source object to multiple other target objects, but it should also be possible for a target object to be connected to multiple source objects, you require a [[Relation]].
+If you want to connect one source object to multiple other target objects, but it should also be possible for a target object to be connected to multiple source objects (n:m relation), you require a [[Relation]].
-Essentially, every individual relation connection is a {{{UBIK}}} object referring both to the source object and the target object (we say, '''left''' and '''right''' target). This allows us to have many such connections for the same left ''and'' right object, whereas a reference property would just enable many connections for the target object (right). For simplicity, let's call the left object '''A''' and the right object '''B'''. '''A''' is related to '''B'''.
+Essentially, every individual relation connection is a {{UBIK}} object referring both to the source object and the target object (we say, '''left''' and '''right''' target). This allows us to have many such connections for the same left ''and'' right object, whereas a reference property would just enable many connections for the target object (right). For simplicity, let's call the left object '''A''' and the right object '''B'''. '''A''' is related to '''B'''.
 In order for two objects to be related, the following requirements must be met:

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 # Set the [[MetaClass]] of '''B''' on the '''TARGETTYPE''' property of the previously created reference, as explained in the HowTo above.
 # Make sure there is a [[MetaProperty]] on the MetaClass of object '''A''' you can use. If necessary, create a new MetaProperty instance and relate it to the MetaClass of '''A''' via the MetaClass to MetaProperty relation ([[HowTo:Add_a_MetaProperty_to_a_MetaClass]]).
-# Set the previously created reference on the new MetaProperty ([[HowTo:Create_a_new_MetaProperty#REFERENCE]]).
+# Set the previously created reference on the new MetaProperty ([[HowTo:Create_a_new_MetaProperty#REFERENCE]]).<br/> [[File:ReferencePropertie.PNG|880 px|border]]
 # Make sure all changes are saved.
 # Open the Bulk Editor for the MetaClass of '''A''' and set the property value for the new MetaProperty on '''A''' to '''B''', in one of the following ways:
 ## dragging and dropping object '''B''' onto the cell
-## selecting the object '''B''' from the dialog appearing after double-clicking the cell
+## selecting the object '''B''' from the dialog appearing after double-clicking the cell <br/>[[File:SelectingObject.PNG|880 px|border]]
 # Save object '''A'''. The connection is now established and can be used, e.g., in the ACM view or by programmatic customizing.

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 Which method fits best depends on the use case and the data model.
 == Connect objects via Reference ==
-If you want one or multiple objects to refer to a single target object each, a reference is what you need. You can either ask an object about the one it refers to, or ask a target object about all objects referring to it via a reference. This is useful, if you want to connect objects but there is no necessity for '''both''' "sides" to be connected to multiple other objects.
+If you want one or multiple objects to refer to a single target object each, a [[Reference]] is what you need. You can either ask an object about the one it refers to, or ask a target object about all objects referring to it via a reference. This is useful, if you want to connect objects but there is no necessity for '''both''' "sides" to be connected to multiple other objects.
 In this case, an object's property contains a link to the target object (respectively, its UID).
 Let's call the target object '''B''' and the object referring to the target object '''A'''. '''A''' refers to '''B'''.
-In order to achieve this, the following requirements must be met:
+In order for an object referring to another object, the following requirements must be met:
 * The MetaClass of object '''A''' must have a respectively configured '''link''' MetaProperty.
 ** The property type should be '''Guid'''.
-** A [[Reference|Reference]] object defining the target MetaClass should be set on the MetaProperty.
+** A [[Reference]] object defining the target MetaClass should be set on the MetaProperty.
 * The property value for the link MetaProperty on object '''A''' must be set to object '''B'''.
 You can achieve this with the following steps:
-* Create a new [[Reference]] ([[HowTo:Create_a_new_Reference]]).
+# Create a new [[Reference]] ([[HowTo:Create_a_new_Reference]]).
-* Set the [[MetaClass]] of '''B''' on the '''TARGETTYPE''' property of the previously created reference, as explained in the HowTo above.
+# Set the [[MetaClass]] of '''B''' on the '''TARGETTYPE''' property of the previously created reference, as explained in the HowTo above.
-* Make sure there is a [[MetaProperty]] on the MetaClass of object '''A''' you can use. If necessary, create a new MetaProperty instance and relate it to the MetaClass of '''A''' via the MetaClass to MetaProperty relation ([[HowTo:Add_a_MetaProperty_to_a_MetaClass]]).
+# Make sure there is a [[MetaProperty]] on the MetaClass of object '''A''' you can use. If necessary, create a new MetaProperty instance and relate it to the MetaClass of '''A''' via the MetaClass to MetaProperty relation ([[HowTo:Add_a_MetaProperty_to_a_MetaClass]]).
-* Set the previously created reference on the new MetaProperty ([[HowTo:Create_a_new_MetaProperty#REFERENCE]]).
+# Set the previously created reference on the new MetaProperty ([[HowTo:Create_a_new_MetaProperty#REFERENCE]]).
-* Make sure all changes are saved.
+# Make sure all changes are saved.
-* Open the Bulk Editor for the MetaClass of '''A''' and set the property value for the new MetaProperty on '''A''' to '''B''', in one of the following ways:
+# Open the Bulk Editor for the MetaClass of '''A''' and set the property value for the new MetaProperty on '''A''' to '''B''', in one of the following ways:
-** dragging and dropping object '''B''' onto the cell
+## dragging and dropping object '''B''' onto the cell
-** selecting the object '''B''' from the dialog appearing after double-clicking the cell
+## selecting the object '''B''' from the dialog appearing after double-clicking the cell
-* Save object '''A'''. The connection is now established and can be used, e.g., in the ACM view or by programmatic customizing.
+# Save object '''A'''. The connection is now established and can be used, e.g., in the ACM view or by programmatic customizing.
 [[Category:How-To|Relate Objects]]

@@ Line 3: / Line 3: @@
 * Use [[Reference|References]] to build up an '''1:n''' relationship between two instances of an entity
-Which method fits best can not be predicted and clearly depends on the use case and the data model.
+Which method fits best depends on the use case and the data model.
 [[Category:How-To|Relate Objects]]

@@ Line 1: / Line 1: @@
 Relating objects is one of the essential parts within {{UBIK}} and can be achieved by two means:
-* Use [[Relation|Relations]] to build up an n:n relationship between two instances of an entity
+* Use [[Relation|Relations]] to build up an '''n:n''' relationship between two instances of an entity
-* Use [[Reference|References]] to build up an 1:n relationship between two instances of an entity
+* Use [[Reference|References]] to build up an '''1:n''' relationship between two instances of an entity
 Which method fits best can not be predicted and clearly depends on the use case and the data model.