When editing a post, the data value should be sent with PHP array notation. Not all fields need to be supplied. If you want to edit the streetName and streetNumber value of the address with id 1234, an example call would be:
/admin/edit/mdb_buildings/plain/editapi?method=edit&hash=HASH
&database=building_addresses&id=1234&data[streetName]=NewStreetName
&data[streetNumber]=12
Please note that editing data in a database propagates that data to other posts. Editing the streetName of an address means that all premises and accessID's connected to this address will have a new streetName