MySQLdb库连接MySQL数据库
Python DB-API是Python的数据库应用程序接口，支持包括Oracle,MySQL,DB2,MSSQL,Sybase等主流数据库，但不同的数据库，需要下载不同的模块，比如说：MySQLdb模块支持MySQL. 虽然模不一样，但所有这些API执行步骤是一致的: 1. 导入API模 2. 获取与数据库的连接
Python DB-API是Python的数据库应用程序接口，支持包括Oracle,MySQL,DB2,MSSQL,Sybase等主流数据库，但不同的数据库，需要下载不同的模块，比如说：MySQLdb模块支持MySQL. 虽然模不一样，但所有这些API执行步骤是一致的:
1. 导入API模
2. 获取与数据库的连接.
3. 发出SQL语句和存储过程.
4. 关闭连接
下面以MySQLdb模块来做说明:
安装
首先必须安装。Windows下载链接:http://www.codegood.com/archives/4
插入
#导入相关模块
import MySQLdb
#建立和mysql数据库的连接
dbconn = MySQLdb.connect(host='127.0.0.1',user='root',passwd='abcd')
#获取游标
cursor = dbconn.cursor()
#执行SQL,创建一个数据库
cursor.execute("drop database if exists test")
cursor.execute("create database test")
#选择连接哪个数据库
dbconn.select_db('test')
#引入异常处理
try:
#执行SQL,创建一个表
cursor.execute("create table log(id int,message varchar(50))")
#插入一条记录
value = [0,"Log Information ID is:0"]
cursor.execute("insert into log values(%s,%s)",value)
#插入多条记录
values = []
for i in range(1,11):
values.append((i,'Log Information ID is:' + str(i)))
cursor.executemany("insert into log values(%s,%s)",values)
#提交修改
dbconn.commit()
except:
#如果执行SQL语句有错，则回滚!
dbconn.rollback()
#关闭游标连接,释放资源
cursor.close()
#关闭连接
dbconn.close()查询
数据库建立连接后，可以使用fetchone()方法来获取单个记录或者fetchAll方法fetech从数据库表的多个值.
fetchone(): 这种方法获取查询结果集的下一行。结果集是一个对象时,将返回一个游标对象用于查询表.
fetchall(): 这种方法获取结果集的所有行。如果某些行已经从结果集中提取，fetchAll()方法检索结果集的其余行.
rowcount: 这是一个只读属性，返回受影响的行数execute()方法.
#导入模块
import MySQLdb
#也可以将数据库名放到Connect()
dbconn = MySQLdb.Connection('127.0.0.1', 'root', 'abcd', 'test')
cursor = dbconn.cursor()
count = cursor.execute('select * from log')
print '总共有 %s 条记录',count
#获取一条记录,每条记录做为一个元组返回
print "只获取一条记录:"
result = cursor.fetchone();
print result
print 'ID: %s Log Info: %s' % result
#获取5条记录，注意由于之前执行有了fetchone()，所以游标已经指到第二条记录了，也就是从第二条开始的所有记录
print "只获取5条记录:"
results = cursor.fetchmany(5)
for res in results:
print res
print "获取所有结果:"
#重置游标位置，0,为偏移量，mode＝absolute | relative,默认为relative,
cursor.scroll(0,mode='absolute')
#获取所有结果
results = cursor.fetchall()
for res in results:
print res
dbconn.close() C:\Work\Python\Learn>python select.py 总共有 %s 条记录 11 只获取一条记录: (0L, 'Log Information ID is:0') ID: 0 Log Info: Log Information ID is:0 只获取5条记录: (1L, 'Log Information ID is:1') (2L, 'Log Information ID is:2') (3L, 'Log Information ID is:3') (4L, 'Log Information ID is:4') (5L, 'Log Information ID is:5') 获取所有结果: (0L, 'Log Information ID is:0') (1L, 'Log Information ID is:1') (2L, 'Log Information ID is:2') (3L, 'Log Information ID is:3') (4L, 'Log Information ID is:4') (5L, 'Log Information ID is:5') (6L, 'Log Information ID is:6') (7L, 'Log Information ID is:7') (8L, 'Log Information ID is:8') (9L, 'Log Information ID is:9') (10L, 'Log Information ID is:10')
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