Extract Rar File

I want to extract rar file instead of ZIP as i am using pre-filled database and size of data is around 1GB and zip makes it 110 MB while rar makes its 70MB which will help me to keep my apk size under 100MB

What data is exactly in the database?
1GB of data is quite a lot for a mobile application.

Actually this mobile app is complete offline and it has around 5Lac of data and we are using pouchdb.
After converting the pouchdb file to sqlie file size of database is around 900MB and indexes are around 170 MB