We work with an existing mysql database under grails which contains a m:n relation. No problem here. But now we are in the situation that i have to add a second n relation entry, which links to the same table and has to be associated to the first n entry.
If it were for the database, I would simply create a table which looks like:
field m_id -> links to m table
field n_id1 -> links to n table
field n_id2 -> links to n table
But how can this be represented in a grails domain class?
Possibly the answer can already be found somewhere, but the searches I did were not successful, maybe due to lack of search term creativity.
EDIT:
Trying to clarify the question: we have a many-to-many relation, but with two items on one side, which have to maintain association to each other (and it also must be clear which is for example the original and which is the replacement item), so they can not be seperated into two separate entries into the relation.
Hmm... try to think of racing car drivers nominating for a series of races, and every nomination has to contain the driver and his substitute. Races would be m (left hand), driver would be n1 and substitute would be n2. (It was really hard work to find an example...)
EDIT:
By coincidence I found this question which addresses the same problem but also left off rather unsolved.