(ii)	Database choice:
One good database solution for NASA Exoplanet Archive would be Cassandra. It’s a great database for data that has a lot of repeated or empty values. Since there are a few columns that are empty on almost every planet (Planet Radius, Planet Density). The way Cassandra stores its values is a number of columns for each row. Also rows can be split into families, which will reduce the number of repeated values (Discovery method, Number of planets in the system etc.)