> A third option, which we already have as it turns out, would be to have it
> as an index:
> dc.title = froissart and rec.collectionIdentifier any "a b c d"
This was always intended (although the discussions may now be in the depths of the list archives) model for doing multiple collection/database searches over SRU/W, i.e. identifying such things as part of the query rather than within another part of the protocol.
Whilst providing the same functionality as the z39.50 style database list, it also allows richers behaviour such as client controlled query adaption e.g.
(dc.title = "The world" and rec.collectionName any "English") or (dc.title = "Le monde" and rec.collectionName any "French")