mysql连接

import pymysql

class DB():
    def __init__(self, host='localhost', port=3306, db='snucs',
                  user='root', passwd='admin123456', charset='utf8mb4'):
        # 建立连接 
        self.conn = pymysql.connect(host=host, port=port, db=db, user=user, passwd=passwd, charset=charset)
        # 创建游标，操作设置为字典类型        
        self.cur = self.conn.cursor(cursor = pymysql.cursors.DictCursor)

    def __enter__(self):
        # 返回游标        
        return self.cur

    def __exit__(self, exc_type, exc_val, exc_tb):
        # 提交数据库并执行        
        self.conn.commit()
        # 关闭游标        
        self.cur.close()
        # 关闭数据库连接        
        self.conn.close()

def local_db():
    return DB()