On Thu, Jul 7, 2011 at 9:19 AM, Dave F. <[email protected]> wrote: > On 07/07/2011 07:41, Anthony wrote: >> >> Thanks Toby. I'm forwarding this to Dave Fox, who is the one who >> actually asked the question. > >> It follows pretty naturally out of the database schema. Anything that >> modifies the ways, way_tags or way_nodes tables creates a new version >> of the way. Things that only affect the node tables such as moving the >> location of a node or changing tags on the node do not affect any of >> the way tables so no new version is created. >> >> The same thing happens with relations and their members. You can add a >> maxspeed= tag to a way and it doesn't affect the relation that way is >> a part of. That would actually make touching long route relations a >> conflict nightmare so I'm pretty glad this isn't the case. > > Thanks to Anthony for asking & Toby for responding. > > However that just explains what happens but not why. > > I suggest that, to most users, if a node within a way is moved then that way > is considered to have been modified & should be recorded as such.
Well, I'm pretty sure I agree with you. Especially if it means we have to go to 64-bit node ids (which means the node id will be as large as the node data!). For the "why", google "database overnormalization". If that doesn't make sense, I'm not sure I can explain it. _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
