如何在Python中连接MySQL数据库？

pip install mysql-connector-python

import mysql.connector

# 建立连接
connection = mysql.connector.connect(
    host="localhost",
    user="your_username",
    password="your_password",
    database="your_database"
)

# 创建游标对象
cursor = connection.cursor()

# 执行查询
query = "SELECT * FROM your_table"
cursor.execute(query)

# 获取结果
results = cursor.fetchall()

# 打印结果
for row in results:
    print(row)

# 关闭连接
cursor.close()
connection.close()

import os
import mysql.connector

# 从环境变量中获取数据库配置
host = os.environ.get('DB_HOST', 'localhost')
user = os.environ.get('DB_USER', 'your_username')
password = os.environ.get('DB_PASSWORD', 'your_password')
database = os.environ.get('DB_NAME', 'your_database')

# 建立连接
connection = mysql.connector.connect(
    host=host,
    user=user,
    password=password,
    database=database
)

# ... 后续代码与之前相同

import mysql.connector
from mysql.connector import Error

try:
    connection = mysql.connector.connect(
        host="localhost",
        user="your_username",
        password="your_password",
        database="your_database"
    )

    cursor = connection.cursor()
    query = "SELECT * FROM your_table"
    cursor.execute(query)
    results = cursor.fetchall()

    for row in results:
        print(row)

except Error as e:
    print(f"Error connecting to MySQL database: {e}")

finally:
    if connection.is_connected():
        cursor.close()
        connection.close()
        print("MySQL connection is closed")

from dbutils.pooled_db import PooledDB
import mysql.connector

# 创建连接池
pool = PooledDB(
    creator=mysql.connector,
    mincached=2,
    maxcached=5,
    host='localhost',
    user='your_username',
    password='your_password',
    database='your_database'
)

# 从连接池中获取连接
connection = pool.connection()

try:
    cursor = connection.cursor()
    query = "SELECT * FROM your_table"
    cursor.execute(query)
    results = cursor.fetchall()

    for row in results:
        print(row)

finally:
    cursor.close()
    connection.close()

cursor.execute(query)
while True:
    row = cursor.fetchone()
    if row is None:
        break
    print(row)