Simon Ward wrote: > Ok, pulling up the wiki page on API 0.6[1] I see that the plan is “to > create an unique index on the combination of object id and tag key”. > Presumably this is mainly for performance. An index doesn’t have to be > unique though—is this a limitation of MySQL or is there some other > reason to enforce uniqueness?
The main reason is that rails works much better if all objects have unique primary keys. In practice keys are unique because although the API has never enforced uniqueness pretty much every client does because all the clients use a hash table of some sort to store tags. Tom -- Tom Hughes (t...@compton.nu) http://www.compton.nu/ _______________________________________________ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
