Python3连接mysql服务

# mysql 操作

import pymysql

'''
Usage mysql module
MySQLDB:
     host=ip or url
     user=db user
     password=db password
     db=database name

     MySQLDB.DDL (execute mysql DDL [insert|update|delete])
        args  sql='update t1 set id=%s where name=%s' condition='(1,"xiaoming")' mode="[update|delete|insert]"
     MySQLDB.DQL (execute mysql DQL [select])
        args  sql='select id,name from t1 where id=%s' condition='(1,)' size=data row number

'''


class MySQLDB():
    def __init__(self,config):
        '''

        :param args: 用于接收未知参数
        :param host: 用于接收数据库ip
        :param user: 用于接收数据库用户
        :param password:  用于接收数据库密码
        :param port: 用于接收数据库端口
        :param db:  用于接收数据库名称
        :param charset: 指定字符集
        '''
        self.conn = pymysql.connect(**config)
        self.cursor = self.conn.cursor()  # 生成游标对象

    def DDL(self, sql, condition, mode):
        try:  # 错误捕捉
            if mode == 'insert':  # 判断模式
                if len(condition) > 1:  # 如果元祖中的元素只有一个，执行cursor.execute，如果不止一个使用cursor.executemany
                    result = self.cursor.executemany(sql, condition)
                else:
                    result = self.cursor.execute(sql, condition)
                print(f'插入完成，受影响{result}行')
            if mode == 'update':
                result = self.cursor.execute(sql)
                print(f'更新完成，受影响{result}行')
            if mode == 'delete':
                result = self.cursor.execute(sql)
                print(f'删除完成，受影响{result}行')
            self.conn.commit()
        except pymysql.MySQLError as e:  # 如果出现错误，打印错误信息并所有执行回滚
            self.conn.rollback()
            print(e)

    def DQL(self, sql, condition=None,
            size=None):  # 查询执行条数调用self.cursor.fetchmany(size)，查询全部使用self.cursor.fetchall(size)
        try:
            result = self.cursor.execute(sql, condition)
            if size:
                result2 = self.cursor.fetchmany(size)
            else:
                result2 = self.cursor.fetchall()
            for i in result2:
                for v in i.values():
                    print('%-20s' % v,end='\t')
                print()
            print(f'共查找{result}条记录')
        except pymysql.MySQLError as e:
            print(e)

    def close(self):
        self.cursor.close()
        self.conn.close()

    def __str__(self):
        return '详细操作手册查看 https://www.baidu.com'


if __name__ == '__main__':  # 测试语句在此行下面编写。
    CONFIG = {
        'user': 'root',
        'host': '127.0.0.1',
        'password': '123456',
        'db': 'mysql',
        'charset': 'utf8',
        'port': 3306,
        'cursorclass': pymysql.cursors.DictCursor
    }
    db = MySQLDB(CONFIG)
    db.DQL('select User,Host from user')
    db.close()