diff --git a/entity/ObjectRelation_entity/ObjectRelation_entity.aod b/entity/ObjectRelation_entity/ObjectRelation_entity.aod
index 5aeb94ee24cd2785d4f62caf643360a7904ca453..5cf415ce65458415ad238fa58de961ae01dd0686 100644
--- a/entity/ObjectRelation_entity/ObjectRelation_entity.aod
+++ b/entity/ObjectRelation_entity/ObjectRelation_entity.aod
@@ -97,6 +97,7 @@
         <entityParameter>
           <name>Object1Type_param</name>
           <expose v="true" />
+          <mandatory v="true" />
         </entityParameter>
         <entityParameter>
           <name>Object1Rowid_param</name>
@@ -141,6 +142,7 @@
         <entityParameter>
           <name>Object2Type_param</name>
           <expose v="true" />
+          <mandatory v="true" />
         </entityParameter>
       </children>
     </entityProvider>
@@ -259,6 +261,7 @@
         <entityParameter>
           <name>AnyObjectType_param</name>
           <expose v="true" />
+          <mandatory v="true" />
         </entityParameter>
       </children>
     </entityProvider>
diff --git a/entity/ObjectRelation_entity/documentation.adoc b/entity/ObjectRelation_entity/documentation.adoc
index 33b4681ecbdb808113aef428f5cd3792a04af1a7..5fd7202aafa4f91fef344ec57f87cfbb216655e0 100644
--- a/entity/ObjectRelation_entity/documentation.adoc
+++ b/entity/ObjectRelation_entity/documentation.adoc
@@ -1,7 +1,47 @@
-== Object Relation ==
+Object Relation
+===============
+:toc2: left
+:numbered:
 
-This entity is for relation between Objects. It should be used if something can be related to something.
-If only special objects should be connected where you always know what it is, it is better to create a custom relation table/entity which is only for this purpose. (e.g. Prod2Prod, Relation, ActitvityLink, ...)
+(how it works currently 13.02.2019)
 
-The Object type is the ID of the context. 
-Use Context_lib for this.
+There are two possible ways for Object Relations:
+
+* With the ObjectRelation_entity
+* With separate entities like the  ActivityLink_entity
+
+== Differences ==
+Relations which use a custom entity are specific for one object. 
+e.g. in ActivityLink are only relations between "activity" and "something".
+In ObjectRelation are relations between "something" and "something".
+
+The activityLink could also be implemented with ObjectRelation, but as there are many activities with many relations.
+So it is better to use an extra db-table.
+
+== How the ObjectRelation_entity works ==
+The entity works with the AB_OBJECTRELATION db-table.
+
+An ObjectRelation always has two Objects which consist of an Object-type and an Object-rowid.
+The object-type is the id of the context. Which you can get by ContextUtils.getCurrentContextId of the Context_lib for the current context.
+The object-rowid is the id of the Object you want use. Normally it is the UID of the Object.
+
+It provides the following providers:
+
+* AnyObject
+* BothObjects
+* Object1
+* Object2
+
+AnyObject is for bidirectional relations and all relations which contain the given AnyObject..._params as Object1 or Object2 will be loaded.
+BothObjects is for relations between two specific objects provided by Object(1|2)..._params.
+Object1 is for unidirectional relations where the Object1 is provided as parameters.
+Object2 is for unidirectional relations where the Object2 is provided as parameters.
+
+For the lookups there are two Entities: Object_entity for the Object-rowids and Context_entity for the Object-type.
+See the documentation for them.
+
+
+The provider use the targetContext-feature to show the preview of the linked objects directly. (see targetContext-docu in the ohers/guide folder)
+
+== Link-entities ==
+They work very similar to the ObjectRelation, but only use one Object. The lookups and targetContext-feature work the same.
\ No newline at end of file
diff --git a/others/guide/TargetContex.adoc b/others/guide/TargetContex.adoc
new file mode 100644
index 0000000000000000000000000000000000000000..89155b20aa2879693555d901cf1f6f5445f002ab
--- /dev/null
+++ b/others/guide/TargetContex.adoc
@@ -0,0 +1,19 @@
+Target Context
+==============
+
+toc2: left
+:numbered:
+
+== What? ==
+The target context is for forwarding the preview and the klick-action to another context.
+
+== Why? ==
+For example the ObjectRelation entity uses this feature to open the linked object directly.
+
+== Where? == 
+It is configured by two properties of the providers.
+
+* targetContextField
+* targetIdField
+
+You can provide an entity-field for each of them which contain the contextId (currently the contextName 13.02.2019) and the rowId (UID) which should be used to open the preview or main view.
\ No newline at end of file