Building vs Building Part

[Azbesciak]

Hi, I am not sure reading the doc, also I did not find any cases for that, so please clarify.
We have building and building_part features. building_part has also a field building_id. Does it mean we have one to many relation between building and building_part, and in building we will have the entity for the given id? So far I rather see that as some virtual entity, which only exists after collecting all parts - that given id does not really has any existing id as a building entity. But I may be wrong - I would even assume from the description, I am.

Thank you!

[jwass]

Hi @Azbesciak - You are correct that the building_part.building_id field is a foreign key reference to the building entity. There's a backward relation in building.has_parts which indicates whether any building_parts exist that point back to this building.

The building entities are the defining record of information about the building - containing things like the type of building (in class and subclass) and the building's name. The building_parts are the 3d representation. But if you only want the 2d geometry, you can find it in building.geometry.

[Azbesciak]

Ok, thank you - I had my assumptions mostly investigating https://explore.overturemaps.org/#17.75/52.404441/16.952647, where if I toggle buildings or building parts, these seem to be exclusive :)

Thank you once again!