local database i would use SQLite.
if u have a mobile app with data access over internet i would use a indirect access via webapi or php.
it belongs what you will do with the collected data.
if it is a hobbie project or not, if u collect data just in wlan
or at any place on this world.
fit the data into phone (ex many pictures) or not.
must the data be at a save place at server for data protection.