数据库交互

什么是数据库的交互?

第一得确定与数据库连接起来

public DbHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
        super(context, name, factory, version);
        Log.i("test","构造方法");
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        Log.i("test","创建表");
        db.execSQL("create table login(uid integer primary key autoincrement,uname,upass)");
    }


    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.i("test","升级数据库版本");
    }
   @Override
   public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
       super.onDowngrade(db, oldVersion, newVers