面向对象对pymysql进行极简单的封装

import pymysql
from pymysql.cursors import DictCursor

class NoDataBaseException(Exception):
    pass

class DBHelper:
    def __init__(self, database=None, host="localhost", port=3306, username="root", password="1234"):
        if database:
            self.conn = pymysql.connect(
                host=host,
                port=port,
                user=username,
                password=password,
                database=database
            )
        else:
            raise NoDataBaseException("没有提供正确的数据库")

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        return self.conn.close()

    def _change(self, sql, *args, isInsert=False):
        cursor = self.conn.cursor(cursor=DictCursor)
        try:
            rownum = cursor.execute(sql, args)
            self.conn.commit()
            if isInsert:
                return cursor.lastrowid
            else:
                return rownum
        except Exception as e:
            print("报错了", e)
            self.conn.rollback()
        finally:
            cursor.close()

    def insert(self, sql, *args):
        return self._change(sql, *args, isInsert=True)

    def update(self, sql, *args):
        return self._change(sql, *args)

    def delete(self, sql, *args):
        return self._change(sql, *args)

    def query_list(self, sql, *args):
        cursor = self.conn.cursor(cursor=DictCursor)
        try:
            cursor.execute(sql, args)
            result = cursor.fetchall()
            return result
        finally:
            cursor.close()

    def query_one(self, sql, *args):
        cursor = self.conn.cursor(cursor=DictCursor)
        try:
            cursor.execute(sql, args)
            result = cursor.fetchone()
            return result
        finally:
            cursor.close()

if __name__ == '__main__':
    with DBHelper("spider") as db:  # ""里面填数据库库名  where 后面的参数 %s ,
        pass
        # 添加数据
        # result = db.insert('insert into stu_new (sname, sgender, sage, score, class) values ("赵e山", 2, 165, 277, "八年六班")')
        # print(result)

        # 修改数据     delete 和 update  俩个一样，调那个都可以
        # result = db.update("update stu_new set sname='王八' where sno = %s", 13)
        # print(result)

        # 删除数据
        # result = db.delete("delete from stu where sno = %s", 13)
        # print(result)

        # 查看所有数据
        # result = db.query_list("select * from stu1")
        # print(result)

        # result = db.query_list("select * from stu1 where gender=%s and address like %s", 1, "%四川%")
        # print(result)

        # # 查看一条数据
        # result = db.query_one("select * from stu_new where sno=%s", 9)
        # print(result)