January 18, 2017
Consider a silly data model to store data about cities like
message City { optional string city_name = 1; optional string state = 2; optional int32 population = 3; optional int32 year_founded = 4; // ... presumably others :-) } and some sample data like:
[ {"city_name": "Portland", "state": "OR", "population": ...}, {"city_name": "Portland", "state": "ME", "population": ...}, {"city_name": "Springfield", "state": "FL", "population": ...}, {"city_name": "Springfield", "state": "IL", "population": .