Android 创建DBHelper类

public class DBHelper extends SQLiteOpenHelper {    private static int mVersion = 1;    private static String name = "apps.db";    public DBHelper(Context context) {        super(context, name, null, mVersion);    }    @Override    public void onCreate(SQLiteDatabase db) {        String sql = "create table book(_id int primary key autoincrememt, name varchar(32) ,price double , publishtime date)";        db.execSQL(sql);    }    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {        String sql = "DROP TABLE IF EXISTS book";        db.execSQL(sql);        this.onCreate(db);    }}