[OSM-dev] JOSM: Several tags with same key

Stefan de Konink stefan at konink.de
Fri Apr 3 02:07:37 BST 2009


Andy Robinson (blackadder-lists) wrote:
> The convention is to separate multiple values for the same key with a
> semicolon.

...and that semantical addition breaks querying for any tool [including 
your database] that follows context free grammar. XML well defines that 
you can use multiple entities, that this API0.6 'wisdom' is still about 
removing multiple keys is not only plain stupid, but also inconsistent 
with previous behavior and queryability of the domain.

Again, the only right way to do is preventing duplicate entries, which 
can easily be enforced using unique(objectid, key, value).

I hope anyone will see the implications for XAPI (the OSM replacements 
that looks like XPath) before it is too late, and what happens if you 
want to find for example amenities that have two values delimited by ';' 
and will not show up with any of these values, unless by default the 
search operation is done by 'LIKE'.



Stefan




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