Hi Jeffry,
A field mapped on a relation is used inside an entity as a container of the related entity/entities.
Thus you can fetch an entity with its related entities enclosed.
Answers of your questions:
1. How can I use a relation when the field mapped on it is hidden?
You can use the relation as filter to fetch your main entity/entities
As you used to use a JOIN between 2 tables just to filter the rows returned from one table.
- Is my understanding correct if I say that the generated relations are for traversing from one entity to related entities? And if I don't have the need to traverse e.g. from entity A to a collection of entity B (1:n), I can safely remove that relation (I'm using Adapter, so I don't need to remove them on both sides)?
Considering the answer of the first question, you still may want the relation for filtering.
Although you might not want to traverse from entity A to a collection of Entity B, you may want to retreive a collection of Entities A who having B.somefield = true