Location and Catchment in Avni

Location Type

• Example of location type is State, District, and Village. Each a different location type) with a parent location type except for State.
• Each location type has a level. A level is a number. Higher-up location types will have a higher number. So the state, district, and village will have numbers 3,2,1 respectively.

Location

• Each location has a location type.
• Location and address_level are the same things.
• Locations are strictly hierarchical.
• The hierarchy is maintained by the parent_id column in the address_level table, location_location_mapping, and also via lineage column. Among these three parent_id columns seems unnecessary.
• location_location_mapping is maintained to handle removal of locations from a parent location without deleting the row. In case of delete location_location_mapping should be voided and this record is synchronised to offline app so that app can also remove the location from mobile db.
• Lineage column is useful in performing hierarchical queries (as the number of levels are not fixed).

Catchment

• The catchment contains a list of locations. The locations can be from different levels also, but usually not.
• Catchment has a list of locations.
• catchment_address_mapping is used for maintaining a list of locations within a catchment.
• Ideally this table should be like location_location_mapping and have voided field so that instead of deleting a row it can be voided the catchment locations can be synced to the mobile app.
• There is virtual_catchment_address_mapping_table function (used as read only table in JPA). This provides all the locations (including descedants) in a catchment. This may be redudant as lineage could be used for it.

Subjects are registered to a location.