Txt, XML or database for backup and restore purpose?

I'm trying to backup & restore SMS and contacts informations and wondering about the way to do that. Keeping in mind that:

1. I want a lightweight app
2. Regarding to reading/writting delays and mechanisms specific to each files type
3. I'm looking for the easiest way to do this b开发者_如何学JAVAackup and restore process.

Which one of .txt , .xml and SQLite .db files will fit my needs? Or there is another efficient way?

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u can use sqLiteDatabase.which is very easy to use.all the things r handled with cursor.which means at a time indicating a single row in a database.check this link: http://www.anddev.org/novice-tutorials-f8/working-with-the-sqlite-database-cursors-t319.html