On 25 Jan 2008, at 16:16, Tom Hughes wrote: > In message <[EMAIL PROTECTED]> > SteveC <[EMAIL PROTECTED]> wrote: > >> On 25 Jan 2008, at 15:37, Tom Hughes wrote: >> >>> In message <[EMAIL PROTECTED]> >>> SteveC <[EMAIL PROTECTED]> wrote: >>> >>>> * needs to know how to update the tile attribute when updating many >>>> nodes (no clue how that's done). Actually it doesn't need to as it >>>> can >>>> just copy the current tile as the node is being deleted not moved. >>>> But >>>> more generally it's probably a good idea if I figure out what's >>>> needed. >>> >>> This is done automatically by a before_save callback in the >>> GeoRecord >>> model that the Node models are derived from. >> >> right, but it's on a per-instance basis? If I want to update 10,000 >> nodes what does it do? > > Well it runs as each node is saved, but the cost relative to the cost > of doing 10000 SQL update statements is probably minimal. > > If you really want to do batch updates you can use the MySQL function > instead (although then you'll have to dodge the rails object model > anyway which I thought you were trying to avoid).
Richards stuff does a lot of things through mass updates... If I delete all the nodes in a way then I dont want to find them all and delete them all. You can instead do Node.delete([1,2,3,4,5]) in rails and so things like Node.update([1,2,3,4,5], :visible => false, :used_id = 42) which is one query instead of 100,000 right? Frankly I couldn't care less, but Richard will scream if the function is slow. But again for the updates and deletions I can just copy the tile attribute from the existing nodes and use that when creating the OldNode's. It's only when mass creating new ones that it matters, and I haven't got to that yet. have fun, SteveC | [EMAIL PROTECTED] | http://www.asklater.com/steve/ _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/dev
