python操作mysql工具类之压缩包1、封装一个不用写SQL语句，只需要填参数的工具类2、封装一个需要自己写SQL语句的

# -*-coding: Utf-8 -*- # @File : date .py # author: 石明亮 # Time：2024/1/31 import pymysql class Database(): # **db是指连接数据库时需要的参数 # 初始化时就连接数据库 def __init__(self, **db): try: # 连接数据库的参数我不希望别人可以动，所以设置私有 self.__conn = pymysql.connect(**db) self.__cursor = self.__conn.cursor() except Exception as e: print("数据库连接失败：\n", e) # 查询一条数据 # 参数：表名table_name,条件factor_str,要查询的字段field 默认是查询所有字段* def select_one(self, table_name, factor_str='', field="*"): if factor_str == '': sql = f"select {field} from {table_name}" else: sql = f"select {field} from {table_name} where {factor_str}" self.__cursor.execute(sql) return self.__cursor.fetchone() # 查询多条数据 # 参数：要查询数据的条数num,表名table_name,条件factor_str,要查询的字段field 默认是查询所有字段* def select_many(self, num, table_name, factor_str='', field="*"): if factor_str == '': sql = f"select {field} from {table_name}" else: sql = f"select {field} from {table_name} where {factor_str}" self.__cursor.execute(sql) return self.__cursor.fetchmany(num) # 查询全部数据 # 参数：表名table_name,条件factor_str,要查询的字段field 默认是查询所有字段* def select_all(self, table_name, factor_str='', field="*"): if factor_str == '': sql = f"select {field} from {table_name}" else: sql = f"select {field} from {table_name} where {factor_str}" self.__cursor.execute(sql) return self.__cursor.fetchall() # 新增数据 def insert(self,table_name, value): sql = f"insert into {table_name} values {value}" try: self.__cursor.execute(sql) self.__conn.commit() print("插入成功") except Exception as e: print("插入失败\n", e) self.__conn.rollback() # 修改数据 # 参数：表名，set值(可能是一个，也可能是多个，所以用字典)，条件 def update(self, table_name, val_obl,change_str): sql = f"update {table_name} set" # set后面应该是要修改的字段，但是可能会修改多个字段的值，所以遍历一下 # key对应字段的名，val对应字段的值 for key, val in val_obl.items(): sql += f" {key} = {val}," # 遍历完的最后面会有一个逗号，所以给它切掉，然后再拼接条件 # !!!空格很重要 sql = sql[:-1]+" where "+change_str try: self.__cursor.execute(sql) self.__conn.commit() print("修改成功") except Exception as e: print("修改失败\n", e) self.__conn.rollback() # 删除数据 def delete(self,table_name, item): sql = f"delete from {table_name} where {item}" try: self.__cursor.execute(sql) self.__conn.commit() print("删除成功") except Exception as e: print("删除失败\n", e) self.__conn.rollback()