Python使用PyMySql增删改查Mysql数据库的实现

CREATE TABLE `users` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(50) NOT NULL,
  `email` varchar(100) NOT NULL,
  `password` varchar(100) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

import pymysql

# 连接MySQL数据库
db = pymysql.connect("localhost", "your_username", "your_password", "your_database")

# 创建一个游标对象cursor
cursor = db.cursor()

import pymysql

# 连接MySQL数据库
db = pymysql.connect("localhost", "your_username", "your_password", "your_database")
# 创建一个游标对象cursor
cursor = db.cursor()
try:
    sql = "SELECT * FROM users WHERE username = %s"
    val = ("test_user",)
    cursor.execute(sql, val)
    results = cursor.fetchall()
    for row in results:
        print(f"ID: {row[0]}, Username: {row[1]}, Email: {row[2]}, Password: {row[3]}")
except Exception as e:
    print(f"查询数据失败: {e}")

import pymysql

# 连接MySQL数据库
db = pymysql.connect("localhost", "your_username", "your_password", "your_database")

# 创建一个游标对象cursor
cursor = db.cursor()
# 插入数据（INSERT）
try:
    sql = "INSERT INTO users (username, email, password) VALUES (%s, %s, %s)"
    val = ("test_user", "test@example.com", "test_password")
    cursor.execute(sql, val)
    db.commit()
    print("插入数据成功")
except Exception as e:
    db.rollback()  # 发生错误时回滚
    print(f"插入数据失败: {e}")

import pymysql

# 连接MySQL数据库
db = pymysql.connect("localhost", "your_username", "your_password", "your_database")

# 创建一个游标对象cursor
cursor = db.cursor()
try:
    sql = "UPDATE users SET email = %s WHERE username = %s"
    val = ("new_email@example.com", "test_user")
    cursor.execute(sql, val)
    db.commit()
    print("更新数据成功")
except Exception as e:
    db.rollback()
    print(f"更新数据失败: {e}")

import pymysql

# 连接MySQL数据库
db = pymysql.connect("localhost", "your_username", "your_password", "your_database")

# 创建一个游标对象cursor
cursor = db.cursor()
try:
    sql = "DELETE FROM users WHERE username = %s"
    val = ("test_user",)
    cursor.execute(sql, val)
    db.commit()
    print("删除数据成功")
except Exception as e:
    db.rollback()
    print(f"删除数据失败: {e}")

cursor.close()
db.close()