[OSM-dev] API 0.5 is on the way
michael_j at email.de
Sat Sep 15 19:07:03 BST 2007
Martijn van Oosterhout wrote:
>> 1) Relation definition which allows any unordered 'member', 'tag'
>> combination, that contains at least one 'member' as child node:
>> <!ELEMENT relation (tag*, member, (member | tag)*)>
> Frederik kicked me for this: he suggests that a relation needs either
> a member or a tag but not both.
Uups. The documentation is vague on this point too. We should update it
with the final resolution.
A relation without a member?? That is probably hard to retrieve back
from the database.
I'd like to understand the use case behind.
According to the DTD Relations may point to Relations:
<!ELEMENT relation ((tag|member)+)>
<!ATTLIST relation id CDATA #REQUIRED>
<!ELEMENT member EMPTY>
<!ATTLIST member type (way|node|relation) #REQUIRED>
<!ATTLIST member ref CDATA #REQUIRED>
This might lead to "Circular referenced Relations". A set of relations
pointing to each other and that have no references to a way or a node.
Independently from the issue above I have below an example, how the DTD
could be extended to cover the complete structure of the payload too.
It also help defining the "Advanced Object Access Methods".
However, if used it has the draw back that we would need to introduce
another child element node below the OSM root node. As it would require
code changes, I am interested to hear if such code changes are useful
enough to get into the code basis.
<!ELEMENT osm (create|retrieve|update|delete)>
<!ELEMENT create (node|relation|way)>
<!ELEMENT retrieve (bound?,(node|relation|way)*)>
<!ELEMENT update ((node|relation|way)*)>
<!ELEMENT delete (node|relation|way)>
<!ELEMENT osm (
<!ELEMENT create_node node>
<!ELEMENT create_way way>
<!ELEMENT create_relation relation>
<!ELEMENT retrieve_node node>
<!ELEMENT retrieve_way way>
<!ELEMENT retrieve_relation relation>
<!ELEMENT retrieve_bounding_box (bound,(node|relation|way)*)>
<!ELEMENT update_node node>
<!ELEMENT update_way way>
<!ELEMENT update_relation relation>
<!ELEMENT delete_node node>
<!ELEMENT delete_way way>
<!ELEMENT delete_relation relation>
+ Rest from 0.5 DTD
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