Python实战之MySQL数据库操作

1. 要想使Python可以操作MySQL数据库，首先需要安装MySQL-python包，在CentOS上可以使用一下命令来安装

$ sudo yum install MySQL-python 

2. 啥都不说了，走两步吧，下面的程序创建了一个到mysql数据库的连接，然后执行了一个简单的查询，并打印查询结果

import MySQLdb  
  
conn = MySQLdb.connect (host = "172.17.23.121", user = "fkong", passwd = "fkong", db = "fkong")  
cursor = conn.cursor ()  
cursor.execute ("SELECT VERSION()")  
row = cursor.fetchone ()  
print "MySQL server version:", row[0]  
cursor.close ()  
conn.close ()  

3. 下面看一个数据库建表和插入操作

import MySQLdb  
  
conn = MySQLdb.connect (host = "172.17.23.121", user = "fkong", passwd = "fkong", db = "fkong")  
cursor = conn.cursor ()  
  
cursor.execute (""" 
    CREATE TABLE TEST 
    ( 
        ID INT, 
        COL1 VARCHAR(40), 
        COL2 VARCHAR(40), 
        COL3 VARCHAR(40) 
    ) 
    """)  
  
cursor.execute (""" 
    INSERT INTO TEST (ID, COL1, COL2, COL3) 
    VALUES 
        (1, 'a', 'b', 'c'), 
        (2, 'aa', 'bb', 'cc'), 
        (3, 'aaa', 'bbb', 'ccc') 
    """)  
  
conn.commit()  
cursor.close ()  
conn.close ()  

4. 下面再来看看查询，查询通常有两种方式：一种是使用cursor.fetchall（）获取所有查询结果，然后再一行一行的迭代；另一种每次通过cursor.fetchone()获取一条记录，直到获取的结果为空为止。看一下下面的例子：

import MySQLdb  
  
conn = MySQLdb.connect (host = "172.17.23.121", user = "fkong", passwd = "fkong", db = "fkong")  
cursor = conn.cursor ()  
  
cursor.execute ("SELECT * FROM TEST")  
rows = cursor.fetchall()  
for row in rows:  
    print "%d, %s, %s, %s" % (row[0], row[1], row[2], row[3])  
  
print "Number of rows returned: %d" % cursor.rowcount  
  
cursor.execute ("SELECT * FROM TEST")  
while (True):  
    row = cursor.fetchone()  
    if row == None:  
        break  
    print "%d, %s, %s, %s" % (row[0], row[1], row[2], row[3])  
      
print "Number of rows returned: %d" % cursor.rowcount  
  
cursor.close ()  
conn.close ()