Using in-memory sqlite android

♀尐吖头ヾ 提交于 2019-12-18 02:10:00

问题



I've been reading, browsing, searching a lot on this, I've criss-crossed stackoverflow back and forth many times and I managed to narrow my problem as much as I could.

The only thing I do not understand, is how to fully use an in-memory SQLite database.

Here is my situation - I have an encrypted SQLite database which I decrypt during the loading of my application (this part works for sure). My class that interacts with the database works for sure with a plain database. So to make it short, everything is flawless with a plain DB which gets loaded from the internal phone memory, but I am not sure how or where to store the decrypted DB in memory so it would get interpreted as normal DB.

I guess I should put null instead of a name in super(context, null, null, 3); and use :memory: instead of a path in SQLiteDatabase.openDatabase(), but I still don't understand fully. It says it cannot find an android_metadata table, but I am certain the database is as it should be.

Hope I was clear on this :)


回答1:


SQLiteOpenHelper() will create an in-memory database if the name is null. Note that it will be created when you invoke getWritableDatabase().

Then you should insert your data.




回答2:


You (or the framework) create a database using ONE of the following:

  • SQLiteDatabase.create()
  • SQLiteDatabase.openDatabase()
  • SQLiteDatabase.openOrCreateDatabase()

The first option is the only way to create a memory-only database, the other two open or create a database file.

Consequently, if you are using SQLiteOpenHelper() and you pass name as null, the framework calls SQLiteDatabase.create(null), so you will get a database that only lives in memory (it dies when close() is called). There is no need to also call one of the other direct methods. Instead call getReadableDatabase() or getWritableDatabase() from your helper.




回答3:


You have to be carefull wile using inmemory as your data will be lost once the db connection is lost. Make sure your db instance is not been closed

https://www.sqlite.org/inmemorydb.html



来源:https://stackoverflow.com/questions/11657191/using-in-memory-sqlite-android

易学教程内所有资源均来自网络或用户发布的内容,如有违反法律规定的内容欢迎反馈
该文章没有解决你所遇到的问题?点击提问,说说你的问题,让更多的人一起探讨吧!