Android Question Database file added in apk file

You really should check available SQL Tutorials, how to work with sqlite. It is all covered there.

Add it in the Files Tab with Add Files, the database file will be added to the Files folder which is the Files.DirAssets folder on the device.
But, you must copy it to another folder on the device!
Database files connot be read nor saved directly to Files.DirAssets.
If the database is used only by your application, copy it to Files.DirInternal.
Otherwise you should copy it to another folder, but you need permissions for that.
You may have a look at the B4X SQLite Database Booklet.