Update many to many relation example

guides/domain-modeling.md

@@ -511,9 +511,9 @@ entity Projects { ...
 entity Users { ...
   projects : Composition of many Members on projects.user = $self;
 }
-entity Members { // link table
-  key project : Association to Projects;
-  key user : Association to Users;
+entity Members: cuid { // link table
+  project : Association to Projects;
+  user : Association to Users;
 }
 ```
 
@@ -529,6 +529,7 @@ entity Users { ...
 ```
 
 Behind the scenes the equivalent of the model above would be generated, with the link table called `Projects.members` and the backlink association to `Projects` in there called `up_`.
+Consider that for SAP Fiori elements 'project' and 'user' shall not be keys, even if their combination is unique, because as keys those fields can't be edited on the UI. In this case a different key is required, for example a UUID, and the unique constraint for `project` and `user` can be expressed via `@assert.unique`.
 
 ### Compositions
 
@@ -570,7 +571,16 @@ entity Orders { ...
 
 [Learn more about Compositions of Aspects in the _CDS Language Reference_](../cds/cdl#managed-compositions){ .learn-more}
 
-Behind the scenes this will add an entity named `Orders.Items` with a backlink association named `up_`, so effectively generating the same model as above.
+Behind the scenes this will add an entity named `Orders.Items` with a backlink association named `up_`, so effectively generating the same model as above. You can annotate the inline composition with UI annotations as follows:
+
+```cds
+annotate Orders.Items with @(
+   UI.LineItem : [
+      {Value: pos},
+      {Value: quantity},
+   ],
+);
+```
 
 ## Aspects