[OSM-dev] Datamodel relation/member constraints

[Frederik Ramm]

Hi,

>> Correct. I would be happy though if writers of editors etc. could act as
>> if the relation members were ordered, and thus upload them in the same
>> sequence they were downloaded. This gives us the option of switching to
 
> In APISs/interfaces there's often a dilemma to make 'life' easier for
> writers or readers.
> Imposing the "same order" is even more demanding for 'data producers' than
> imposing an ordering.
> I would not recommend both in order to make APIs simple.

I don't quite understand what you mean: The API will not change one 
millimetre by making relations ordered.

I am relatively sure that we will have ordered relations *some day*
because they are required for some things, for example a bus route
relation where the bus uses the same bit of road twice on its route.

If editing software today makes sure that elements are written back 
in the order they are retrieved (even though we don't have ordered
relations yet), then the software is already prepared for a future
time when relations might be ordered.

If, on the other hand, the editor throws relation members into a 
container that doesn't guarantee ordering, then the editor will have
to be changed when ordered relations are introduced.

That's all I wanted to say.

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"