Android：Sqlite 常见两个类SQLiteOpenHelper，SQLiteDatabase 随记

1）SQLiteOpenHelper:作用管理数据库的创建和版本的管理

官方英文表达：
A helper class to manage database creation and version management.

You create a subclass implementing {@link #onCreate}, {@link #onUpgrade} and
optionally {@link #onOpen}, and this class takes care of opening the database
if it exists, creating it if it does not, and upgrading it as necessary.

2）SQLiteDatabase：

官方英文表达：

Exposes methods to manage a SQLite database. SQLiteDatabase has methods to create, delete, execute SQL commands, and perform other common database management tasks. execSQL(sql) rawQuery delete update insert