[dev] Horde RDO: retrieve sorted

[Sebastian Birnbach]

I have a ONE:MANY relationship between data types A and B. With Horde RDO
accessing a B from a given A is as easy as A->B[i].

When there are several B elements I would like them to come in a
predetermined order. For instance, elements B might each have an element x
and A->B could return the collection of elements B sorted by x in
descending order:

A->B[0]->x > A->B[1]->x > A->B[2]->x ...

It is clear that the sorting could be accomplished through the right SQL
statements. Can RDO be persuaded to do this for me?