增删改查数据库例子

import mysql.connector

# 连接到MySQL数据库
db = mysql.connector.connect(
    host="localhost",
    user="yourusername",
    password="yourpassword",
    database="yourdatabase"
)

cursor = db.cursor()

# 增（Create）
sql_insert = "INSERT INTO users (name, email) VALUES (%s, %s)"
values = ("John Doe", "john@example.com")
cursor.execute(sql_insert, values)
db.commit()

# 查（Read）
sql_select = "SELECT * FROM users WHERE name = %s"
cursor.execute(sql_select, ("John Doe",))
result = cursor.fetchall()
for row in result:
    print(row)

# 改（Update）
sql_update = "UPDATE users SET email = %s WHERE name = %s"
cursor.execute(sql_update, ("john_new@example.com", "John Doe"))
db.commit()

# 删（Delete）
sql_delete = "DELETE FROM users WHERE name = %s"
cursor.execute(sql_delete, ("John Doe",))
db.commit()

# 关闭数据库连接
cursor.close()
db.close()