Python连接MySQL数据库之pymysql模块使用（1）

01Python登录.py

username = input("输入用户名：")pwd = input("请输入密码：")

# if username == "erge" and pwd == "dashabi":#     print("登陆成功！")# else:#     print("滚~")

with open("userinfo.txt", "r", encoding="utf-8") as f:    for line in f:        # print(line.strip())        u, p = line.strip().split("|")        if u == username and p == pwd:            print("登陆成功！")            break    else:        print("go out~")

02Python连接数据库登录.py

import pymysql

username = input("输入用户名：")pwd = input("请输入密码：")

# if username == "erge" and pwd == "dashabi":#     print("登陆成功！")# else:#     print("滚~")

# 拿到用户输入的用户名密码

# 去数据库里面判断用户名和密码是否正确# 1. 连接数据库conn = pymysql.connect(    host="localhost",    port=3306,  # 端口号是数字类型    database="userinfo",  # 写自己本地的数据库名字    user="root",    password="123456",    charset="utf8"   # 千万记得没有-)

cursor = conn.cursor()  # 获取输入SQL语句的光标对象sql = "select * from info;"ret = cursor.execute(sql)print(ret)# 关闭连接cursor.close()conn.close()

# 2. 判断 --> 只需要把检索条件写到sql语句中，去数据库执行就可以了

# with open("userinfo.txt", "r", encoding="utf-8") as f:#     for line in f:#         # print(line.strip())#         u, p = line.strip().split("|")#         if u == username and p == pwd:#             print("登陆成功！")#             break#     else:#         print("go out~")

03登录校验MySQL.py

import pymysql

# 获取用户输入username = input("输入用户名：")pwd = input("请输入密码：")

# 连接数据库检索有没有该用户conn = pymysql.connect(    host="localhost",    port=3306,    database="userinfo",    user="root",    password="123456",    charset="utf8")

cursor = conn.cursor()  # 获取光标# 拼接要执行的SQL语句sql = "select * from info where username=‘%s‘ and password=‘%s‘" % (username, pwd)print(sql)print("=" * 120)# 执行SQL语句ret = cursor.execute(sql)if ret:    print("登录成功")else:    print("登录失败！")# 关闭光标对像cursor.close()# 关闭连接conn.close()

04登录校验MySQL规避SQL注入.py

import pymysql

# 获取用户输入username = input("输入用户名：")pwd = input("请输入密码：")

# 连接数据库检索有没有该用户conn = pymysql.connect(    host="localhost",    port=3306,    database="userinfo",    user="root",    password="123456",    charset="utf8")

cursor = conn.cursor()  # 获取光标# 拼接要执行的SQL语句sql = ‘select * from info where username=%s and password=%s‘print(sql)print("=" * 120)# 执行SQL语句ret = cursor.execute(sql, [username, pwd])  # 让pymysql帮我们拼接SQL语句if ret:    print("登录成功")else:    print("登录失败！")# 关闭光标对像cursor.close()# 关闭连接conn.close()

05pymysql增操作.py

"""pymysql增操作"""

import pymysql

conn = pymysql.connect(    host="localhost",    port=3306,    database="userinfo",    user="root",    password="123456",    charset="utf8")

cursor = conn.cursor()

# 拼接语句sql = "insert into info (username, password)VALUES (%s, %s)"# 执行try:    cursor.execute(sql, ["大旭",])    # 自己写个for循环 (今天作业自己试下)    conn.commit()except Exception as e:    print("报错啦：",str(e))    conn.rollback()  # 回滚# 对数据库做写操作一定要记得提交assword

cursor.close()conn.close()

06演示lastrowid有什么用.py

import pymysql

conn = pymysql.connect(    host="localhost",    port=3306,    database="userinfo",    user="root",    password="123456",    charset="utf8")

cursor = conn.cursor()# 创建班级的sql语句sql1 = "insert into class (name) VALUES (%s)"# 创建学生的sql语句sql2 = "insert into student (name, cid) VALUES (%s, %s)"

cursor.execute(sql1, "全栈9期")new_id = cursor.lastrowid  # 获取刚插入数据的ID值cursor.execute(sql2, ["小东北", new_id])

conn.commit()cursor.close()conn.close()

07批量插入数据.py

import pymysql

conn = pymysql.connect(    host="localhost",    port=3306,    database="userinfo",    user="root",    password="123456",    charset="utf8")

cursor = conn.cursor()# 创建班级的sql语句sql = "insert into info (username, password) VALUES (%s, %s)"

data = [("alex1", "dashabi"), ("污Sir1",), ("xiaoyima1", "nvshen")]try:    cursor.executemany(sql, data)  # 内部实现for循环，批量执行插入语句    # for i in data:    #     cursor.execute(sql, i)    conn.commit()  # 提交一次except Exception as e:    print("错啦！")    conn.rollback()

cursor.close()conn.close()

08删除数据操作.py

import pymysql

conn = pymysql.connect(    host="localhost",    port=3306,    database="userinfo",    user="root",    password="123456",    charset="utf8")

cursor = conn.cursor()

# sql = "delete from info WHERE username=%s"sql = "delete from info WHERE id=%s"

cursor.execute(sql,8)

conn.commit()cursor.close()conn.close()

原文地址：https://www.cnblogs.com/mys6/p/11278758.html