如何使用Python连接MySQL数据库？

此示例开箱即用.除了使用peewee(pip install peewee)之外别无其他.

这是一种方法:

#!/usr/bin/python
import MySQLdb

# Connect
db = MySQLdb.connect(host="localhost",
                     user="appuser",
                     passwd="",
                     db="onco")

cursor = db.cursor()

# Execute SQL select statement
cursor.execute("SELECT * FROM location")

# Commit your changes if writing
# In this case, we are only reading data
# db.commit()

# Get the number of rows in the resultset
numrows = cursor.rowcount

# Get and display one row at a time
for x in range(0, numrows):
    row = cursor.fetchone()
    print row[0], "-->", row[1]

# Close the connection
db.close()

参考这里

Oracle(MySQL)现在支持纯Python连接器.这意味着不需要安装二进制文件:它只是一个Python库.它被称为"连接器/ Python".

http://dev.mysql.com/downloads/connector/python/

如果你不需要MySQLdb,但是会接受任何库,我非常非常推荐来自MySQL的MySQL Connector/Python:http://dev.mysql.com/downloads/connector/python/.

它是一个包(大约110k),纯Python,所以它是独立于系统的,并且安装简单.您只需下载,双击,确认许可协议即可.不需要Xcode,MacPorts,编译,重启......

然后连接如下:

import mysql.connector    
cnx = mysql.connector.connect(user='scott', password='tiger',
                              host='127.0.0.1',
                              database='employees')

try:
   cursor = cnx.cursor()
   cursor.execute("""
      select 3 from your_table
   """)
   result = cursor.fetchall()
   print result
finally:
    cnx.close()

如果你想避免安装mysql头只是为了从python访问mysql,请停止使用MySQLDb.

使用pymysql.它完成了MySQLDb的所有功能,但它完全是在没有外部依赖性的 Python中实现的.这使得所有操作系统上的安装过程一致且简单. pymysql是MySQLDb和恕我直言的替代品,没有理由将MySQLDb用于任何事情......永远!- PTSD from installing MySQLDb on Mac OSX and *Nix systems,那只是我.

安装

pip install pymysql

就是这样......你准备好了.

来自pymysql Github repo的示例用法

import pymysql.cursors
import pymysql

# Connect to the database
connection = pymysql.connect(host='localhost',
                             user='user',
                             password='passwd',
                             db='db',
                             charset='utf8mb4',
                             cursorclass=pymysql.cursors.DictCursor)

try:
    with connection.cursor() as cursor:
        # Create a new record
        sql = "INSERT INTO `users` (`email`, `password`) VALUES (%s, %s)"
        cursor.execute(sql, ('webmaster@python.org', 'very-secret'))

    # connection is not autocommit by default. So you must commit to save
    # your changes.
    connection.commit()

    with connection.cursor() as cursor:
        # Read a single record
        sql = "SELECT `id`, `password` FROM `users` WHERE `email`=%s"
        cursor.execute(sql, ('webmaster@python.org',))
        result = cursor.fetchone()
        print(result)
finally:
    connection.close()

另外 - 快速透明地替换现有代码中的MySQLdb

如果你有使用MySQLdb的现有代码,你可以使用这个简单的过程轻松地用pymysql替换它:

# import MySQLdb << Remove this line and replace with:
import pymysql
pymysql.install_as_MySQLdb()

对MySQLdb的所有后续引用都将透明地使用pymysql.

尝试使用MySQLdb

这里有一个页面:http://www.kitebird.com/articles/pydbapi.html

从页面:

# server_version.py - retrieve and display database server version

import MySQLdb

conn = MySQLdb.connect (host = "localhost",
                        user = "testuser",
                        passwd = "testpass",
                        db = "test")
cursor = conn.cursor ()
cursor.execute ("SELECT VERSION()")
row = cursor.fetchone ()
print "server version:", row[0]
cursor.close ()
conn.close ()

作为db驱动程序,还有我们的.在该链接上列出的一些原因,说明为什么我们的更好:

oursql具有真正的参数化,完全将SQL和数据完全发送到MySQL.

oursql允许将文本或二进制数据流式传输到数据库并从数据库流出,而不是要求在客户端中缓存所有内容.

oursql可以懒惰地插入行并且懒惰地获取行.

oursql默认支持unicode.

oursql支持python 2.4到2.7,在2.6+上没有任何弃用警告(参见PEP 218),并且2.7没有完全失败(参见PEP 328).

oursql在python 3.x上原生运行.

那么如何使用oursql连接mysql？

与mysqldb非常相似:

import oursql

db_connection = oursql.connect(host='127.0.0.1',user='foo',passwd='foobar',db='db_name')
cur=db_connection.cursor()
cur.execute("SELECT * FROM `tbl_name`")
for row in cur.fetchall():
    print row[0]

文档中的教程相当不错.

当然,对于ORM,SQLAlchemy是一个不错的选择,正如其他答案中已经提到的那样.

SQLAlchemy是Python SQL工具包和Object Relational Mapper,它为应用程序开发人员提供了SQL的全部功能和灵活性.SQLAlchemy提供了一整套众所周知的企业级持久性模式,专为高效和高性能的数据库访问而设计,适用于简单的Pythonic域语言.

安装

pip install sqlalchemy

RAW查询

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, scoped_session

engine = create_engine("mysql://:@/")
session_obj = sessionmaker(bind=engine)
session = scoped_session(session_obj)

# insert into database
session.execute("insert into person values(2, 'random_name')")
session.flush()
session.commit()

ORM的方式

from sqlalchemy import Column, Integer, String
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, scoped_session

Base = declarative_base()
engine = create_engine("mysql://:@/")
session_obj = sessionmaker(bind=engine)
session = scoped_session(session_obj)

# Bind the engine to the metadata of the Base class so that the
# declaratives can be accessed through a DBSession instance
Base.metadata.bind = engine

class Person(Base):
    __tablename__ = 'person'
    # Here we define columns for the table person
    # Notice that each column is also a normal Python instance attribute.
    id = Column(Integer, primary_key=True)
    name = Column(String(250), nullable=False)

# insert into database
person_obj = Person(id=12, name="name")
session.add(person_obj)
session.flush()
session.commit()

尽管有上述所有答案,但如果您不想提前连接到特定数据库,例如,如果您想要创建数据库(!),则可以使用connection.select_db(database),如下所示.

import pymysql.cursors
connection = pymysql.connect(host='localhost',
                         user='mahdi',
                         password='mahdi',
                         charset='utf8mb4',
                         cursorclass=pymysql.cursors.DictCursor)
cursor = connection.cursor()
cursor.execute("CREATE DATABASE IF NOT EXISTS "+database)
connection.select_db(database)
sql_create = "CREATE TABLE IF NOT EXISTS "+tablename+(timestamp DATETIME NOT NULL PRIMARY KEY)"
cursor.execute(sql_create)
connection.commit()
cursor.close()

MySQLdb是直截了当的方式.您可以通过连接执行SQL查询.期.

我喜欢的方式也是pythonic,而是使用强大的SQLAlchemy.这是一个与查询相关的教程,这是一个关于SQLALchemy的ORM功能的教程.

在终端中运行以下命令以安装mysql连接器：

pip install mysql-connector-python

并在python编辑器中运行此命令以连接到MySQL：

import mysql.connector

mydb = mysql.connector.connect(
      host="localhost",
      user="yourusername",
      passwd="yourpassword",
      database="mydatabase"
)

执行MySQL命令的示例（在python edior中）：

mycursor = mydb.cursor()
mycursor.execute("CREATE TABLE customers (name VARCHAR(255), address VARCHAR(255))")    
mycursor.execute("SHOW TABLES")

mycursor.execute("INSERT INTO customers (name, address) VALUES ('John', 'Highway 21')")    
mydb.commit() # Use this command after insert or update

有关更多命令：https : //www.w3schools.com/python/python_mysql_getstarted.asp

只是修改上面的答案.只需运行此命令即可为python安装mysql

sudo yum install MySQL-python
sudo apt-get install MySQL-python

记得!它区分大小写.

对于Python3.6，我发现了两个驱动程序：pymysql和mysqlclient。我测试了它们之间的性能并得到了结果：mysqlclient更快。

以下是我的测试过程（需要安装python lib profilehooks来分析时间流逝吗？

原始SQL： select * from FOO;

在mysql终端中立即执行： 46410 rows in set (0.10 sec)

pymysql（2.4秒）：

from profilehooks import profile
import pymysql.cursors
import pymysql
connection = pymysql.connect(host='localhost', user='root', db='foo')
c = connection.cursor()

@profile(immediate=True)
def read_by_pymysql():
    c.execute("select * from FOO;")
    res = c.fetchall()

read_by_pymysql()

这是pymysql配置文件：

mysqlclient（0.4秒）

from profilehooks import profile
import MySQLdb

connection = MySQLdb.connect(host='localhost', user='root', db='foo')
c = connection.cursor()

@profile(immediate=True)
def read_by_mysqlclient():
    c.execute("select * from FOO;")
    res = c.fetchall()

read_by_mysqlclient()

这是mysqlclient配置文件：

因此，似乎mysqlclient比pymysql快得多