[OSM-dev] Alternative PostgreSQL Schema

[Brett Henderson]

Martijn van Oosterhout wrote:
> On 10/24/07, Brett Henderson <brett at bretth.com> wrote:
>   
>> An OSM data element's visible status may change many times over its
>> lifecycle.  A visible flag of false is a logical delete, but records can
>> be undeleted on a subsequent version.  The visible flag on the history
>> tables doesn't indicate which data is current.
>>     
>
> Oh? Last time I tried it wasn't possible to undelete things. Did this
> change with the 0.5 port?
>
> Have a nice day,
>   
Probably not.  I'm just basing this on the data I found in the old 
database schema.  I'm pretty sure node 2 was one of the nodes that had 
been deleted and re-created again.  If it is no longer possible then 
that is probably good news, it complicates many things.  If undelete is 
never required it might simplify things considerably.

One other thing I've been thinking about is changeset grouping for the 
purposes of reverting changes.  If that gets introduced one day it might 
be neat to be able to restore old ids.  Not sure if that should be 
catered for or not.