The principle of SQLite's lock:

The principle of SQLite locking:

http://www.cnblogs.com/huozhong/p/5973938.html
http://www.sqlite.org/lockingv3.html
http://www.cnblogs.com/wangmars/p/ 4530670.html
http://blog.csdn.net/u010205141/article/details/44182461
https://stackoverflow.com/questions/6675240/is-sqlite-database-instance-thread-safe
http://droidyue.com /blog/2015/12/13/android-sqlite-tuning/#