连接mysql数据库代码

在Python中连接MySQL数据库通常使用mysql-connector-python库。首先，你需要安装这个库，可以使用pip进行安装：

pip install mysql-connector-python

接下来，

python
import mysql.connector

# 连接MySQL数据库
try:
    connection = mysql.connector.connect(
        host='your_host',
        user='your_username',
        password='your_password',
        database='your_database_name'
    )

    if connection.is_connected():
        db_Info = connection.get_server_info()
        print("Connected to MySQL Server version ", db_Info)
        cursor = connection.cursor()
        cursor.execute("select database();")
        record = cursor.fetchone()
        print("You're connected to database: ", record)

except mysql.connector.Error as e:
    print("Error while connecting to MySQL", e)

# 关闭连接
finally:
    if connection.is_connected():
        cursor.close()
        connection.close()
        print("MySQL connection is closed")

在这个示例中：

替换your_host，your_username，your_password，your_database_name为你的实际数据库主机、用户名、密码和数据库名称。mysql.connector.connect()方法用于建立与MySQL数据库的连接。通过connection.cursor()创建一个游标对象，用于执行SQL查询。最后，别忘记在完成操作后关闭数据库连接。

这是一个基本的示例，你可以根据自己的需求进行调整和扩展。

当连接成功建立后，你可以执行各种操作，如执行SQL查询、插入、更新或删除数据等。

执行SQL查询

python
# 执行SQL查询
query = "SELECT * FROM your_table;"
cursor.execute(query)
rows = cursor.fetchall()
for row in rows:
    print(row)

插入数据

python
# 插入数据
insert_query = "INSERT INTO your_table (column1, column2, column3) VALUES (%s, %s, %s);"
data = ('value1', 'value2', 'value3')
cursor.execute(insert_query, data)
connection.commit()  # Commit changes to the database
print("Data inserted successfully")

更新数据

python
# 更新数据
update_query = "UPDATE your_table SET column1 = %s WHERE condition;"
new_value = 'new_value'
cursor.execute(update_query, (new_value,))
connection.commit()  # Commit changes to the database
print("Data updated successfully")

删除数据

python
# 删除数据
delete_query = "DELETE FROM your_table WHERE condition;"
cursor.execute(delete_query)
connection.commit()  # Commit changes to the database
print("Data deleted successfully")

记得在执行修改数据库的操作时，使用connection.commit()方法来提交事务，以确保更改生效。