import mysql.connector

class MysqlDb():
    __db_config = {
    'host':'xxx.xxx.xxx',
    'port':3306,
    'username':'root',
    'password':'password',
    'database':'dataname',
    'charset':'utf8'
    }
    def __init__(self,host=__db_config['host'],port=__db_config['port'],user=__db_config['username'],passwd=__db_config['password'],db=__db_config['database'],charset=__db_config['charset']):
        try:
           self.connection = mysql.connector.connect(host=host,port=port,user=user,passwd=passwd,db=db,charset=charset)
        except mysql.connector.Error as e:
            print("Connect Database Failed.",str(e))
        self.cursor = self.connection.cursor(buffered=True)
     # 查询所有
    def fetchall(self, sql):
         try:
             self.__execute(sql)
             return self.cursor.fetchall()
         except Exception as error:
             print(error)
    # 查询多条数据
    def fetchmany(self, sql, size=1):
         try:
             self.__execute(sql)
             return self.cursor.fetchmany(size)
         except Exception as error:
             print(error)
    # 查询一条数据
    def fetchone(self, sql):
         try:
             self.__execute(sql)
             return self.cursor.fetchone()
         except Exception as error:
             print(error)
    # 增删改的方法
    def change(self, sql):
         try:
             self.__execute(sql)
             self.connection.commit()
         except Exception as error:
             print(error)
    # 执行的私有方法
    def __execute(self, sql):
         self.cursor.execute(sql)
    # 关闭连接和游标
    def __del__(self):
         self.connection.close()

import MysqlDb as mdb

def main():
    db=mdb.MysqlDb()  
    db.change('insert into test (test)value ("ddd")')
    db.change('delete from test where id=3')
    db.change('update test set test="fff" where id=4')
    rows=db.fetchall('Select * from test')
    for row in rows:
        print(row)
    print(db.fetchmany('Select * from test',2))
    print(db.fetchone('Select * from test'))

main()