Am 06.06.2013, 23:36 Uhr, schrieb Michael Bayer <[email protected]>:
On Jun 6, 2013, at 5:18 PM, Charlie Clark
<[email protected]> wrote:
Am 06.06.2013, 20:21 Uhr, schrieb Andy <[email protected]>:
IOW I have things and groups. The rel table is a many-to-many relation
between things and groups. A thing also may have a favorite group; if
so,
there has to be a rel between that thing and its favorite group.
Are favourites optional? Why not normalise to Favourites with strict
1:1 with things and groups?
by putting the FK constraint to the composite primary key of "rel", it
guarantees that the "favorite" item is a member of the thing->groups
collection.
I understand that I just wonder whether every thing has a favourite or
not, in which case the structure is not fully normalised and that is how I
would do it because it makes the projections easier. Well, to my mind at
least. And, wouldn't it resolve the join problem?
Charlie
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