Android database security: after the user exits, the transaction rollback log still stores relevant data information

details ：
/data/data/package_name/databases/dday-db
/data/data/package_name/databases/dday-db-shm
/data/data/package_name/databases/dday-db-wal

Introduce ：shm and wal
The Android implementation for a SQLite database is normally in WAL (write-ahead log) mode. This uses 3 files in the background: The first with the name of your database (i.e. my_db, the second one with that name and the “-shm” suffix (my_db-shm) and the third one with the “-wal” suffix (my_db-wal). The -wal file will save changes.

Solution ：
One ： Close and then open the database , Automatically delete files
Two ： When opening the database , close write-ahead log mode