[OSM-dev] API Logic

[Tom Hughes]

In message <5668239F-D932-4A5A-B18D-AA39DBC3A2AE at asklater.com>
        SteveC <steve at asklater.com> wrote:

> On 25 Jan 2008, at 15:37, Tom Hughes wrote:
>
>> In message <85B67797-8971-4352-98A9-13DFD451AE3E at asklater.com>
>>        SteveC <steve at asklater.com> 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).

Tom

-- 
Tom Hughes (tom at compton.nu)
http://www.compton.nu/