Python使用PyGreSQL操作PostgreSQL数据库教程


            PostgreSQL是一款功能强大的开源关系型数据库，本文使用python实现了对开源数据库PostgreSQL的常用操作，其开发过程简介如下：

一、环境信息： 

   1、操作系统：

        RedHat Enterprise Linux 4

        Windows XP SP2

  2、数据库：

        PostgreSQL8.3

  3、 开发工具:

        Eclipse+Pydev+python2.6+PyGreSQL(提供pg模块)

  4、说明：

        a、PostgreSQL数据库运行于RedHat Linux上，Windows下也要安装pgAdmin（访问PostgreSQL服务器的客户端）。

        b、PyGreSQL(即pg)模块下载路径及API手册：http://www.pygresql.org/

 PyGreSQL模块点此本站下载

二、配置：

       1、将pgAdmin安装路径下以下子目录添加到系统环境变量中:

             E:\Program Files\PostgreSQL\8.3\lib

             E:\Program Files\PostgreSQL\8.3\bin

       2、将python安装目录C:\Python26\Lib\site-packages\pywin32_system32下的dll文件拷贝到C:\WINDOWS\system32

       3、说明：如果跳过以上两步，在import pg时将会报错，并且会浪费较长时间才能搞定。

三、程序实现：





#!/usr/bin/env python

# -*- coding: utf-8 -*-



#导入日志及pg模块

import logging

import logging.config

import pg



#日志配置文件名

LOG_FILENAME = 'logging.conf'



#日志语句提示信息

LOG_CONTENT_NAME = 'pg_log'



def log_init(log_config_filename, logname):

  '''

  Function:日志模块初始化函数

  Input：log_config_filename:日志配置文件名

      lognmae:每条日志前的提示语句

  Output: logger

  author: socrates

  date:2012-02-12

  '''

  logging.config.fileConfig(log_config_filename)

  logger = logging.getLogger(logname)

  return logger



def operate_postgre_tbl_product():

  '''

  Function:操作pg数据库函数

  Input：NONE

  Output: NONE

  author: socrates

  date:2012-02-12

  ''' 

  pgdb_logger.debug("operate_postgre_tbl_product enter...") 

  

  #连接数据库 

  try:

    pgdb_conn = pg.connect(dbname = 'kevin_test', host = '192.168.230.128', user = 'dyx1024', passwd = '888888')

  except Exception, e:

     print e.args[0]

     pgdb_logger.error("conntect postgre database failed, ret = %s" % e.args[0])  

     return  

   

  pgdb_logger.info("conntect postgre database(kevin_test) succ.") 

    

  #删除表

  sql_desc = "DROP TABLE IF EXISTS tbl_product3;"

  try:

    pgdb_conn.query(sql_desc)

  except Exception, e:

    print 'drop table failed'

    pgdb_logger.error("drop table failed, ret = %s" % e.args[0])

    pgdb_conn.close() 

    return

  

  pgdb_logger.info("drop table(tbl_product3) succ.") 

 

  #创建表

  sql_desc = '''CREATE TABLE tbl_product3(

    i_index INTEGER,

    sv_productname VARCHAR(32)

    );'''

  try:  

    pgdb_conn.query(sql_desc)

  except Exception, e:

    print 'create table failed'

    pgdb_logger.error("create table failed, ret = %s" % e.args[0])

    pgdb_conn.close() 

    return    

  

  pgdb_logger.info("create table(tbl_product3) succ.") 

   

  #插入记录  

  sql_desc = "INSERT INTO tbl_product3(sv_productname) values('apple')"

  try:

    pgdb_conn.query(sql_desc)

  except Exception, e:

    print 'insert record into table failed'

    pgdb_logger.error("insert record into table failed, ret = %s" % e.args[0])

    pgdb_conn.close() 

    return  

   

  pgdb_logger.info("insert record into table(tbl_product3) succ.")   

   

  #查询表 1    

  sql_desc = "select * from tbl_product3"

  for row in pgdb_conn.query(sql_desc).dictresult():

    print row

    pgdb_logger.info("%s", row) 

 

  #查询表2    

  sql_desc = "select * from tbl_test_port"

  for row in pgdb_conn.query(sql_desc).dictresult():

    print row 

    pgdb_logger.info("%s", row)    

   

  #关闭数据库连接   

  pgdb_conn.close()    

  pgdb_logger.debug("operate_sqlite3_tbl_product leaving...") 



if __name__ == '__main__': 

  

  #初始化日志系统

  pgdb_logger = log_init(LOG_FILENAME, LOG_CONTENT_NAME)  

  

  #操作数据库

  operate_postgre_tbl_product()

  





四、测试：



 1、运行后命令行打印结果：





{'sv_productname': 'apple', 'i_index': None}

{'i_status': 1, 'i_port': 2, 'i_index': 1}

{'i_status': 1, 'i_port': 3, 'i_index': 2}

{'i_status': 1, 'i_port': 5, 'i_index': 3}

{'i_status': 1, 'i_port': 0, 'i_index': 5}

{'i_status': 1, 'i_port': 18, 'i_index': 7}

{'i_status': 1, 'i_port': 8, 'i_index': 8}

{'i_status': 1, 'i_port': 7, 'i_index': 9}

{'i_status': 1, 'i_port': 21, 'i_index': 10}

{'i_status': 1, 'i_port': 23, 'i_index': 11}

{'i_status': 1, 'i_port': 29, 'i_index': 12}

{'i_status': 1, 'i_port': 3000, 'i_index': 4}

{'i_status': 1, 'i_port': 1999, 'i_index': 6}







2、日志文件内容：





[2012-02-12 18:09:53,536 pg_log]DEBUG: operate_postgre_tbl_product enter... (test_func.py:36)

[2012-02-12 18:09:53,772 pg_log]INFO: conntect postgre database(kevin_test) succ. (test_func.py:46)

[2012-02-12 18:09:53,786 pg_log]INFO: drop table(tbl_product3) succ. (test_func.py:58)

[2012-02-12 18:09:53,802 pg_log]INFO: create table(tbl_product3) succ. (test_func.py:73)

[2012-02-12 18:09:53,802 pg_log]INFO: insert record into table(tbl_product3) succ. (test_func.py:85)

[2012-02-12 18:09:53,802 pg_log]INFO: {'sv_productname': 'apple', 'i_index': None} (test_func.py:91)

[2012-02-12 18:09:53,802 pg_log]INFO: {'i_status': 1, 'i_port': 2, 'i_index': 1} (test_func.py:97)

[2012-02-12 18:09:53,802 pg_log]INFO: {'i_status': 1, 'i_port': 3, 'i_index': 2} (test_func.py:97)

[2012-02-12 18:09:53,802 pg_log]INFO: {'i_status': 1, 'i_port': 5, 'i_index': 3} (test_func.py:97)

[2012-02-12 18:09:53,802 pg_log]INFO: {'i_status': 1, 'i_port': 0, 'i_index': 5} (test_func.py:97)

[2012-02-12 18:09:53,819 pg_log]INFO: {'i_status': 1, 'i_port': 18, 'i_index': 7} (test_func.py:97)

[2012-02-12 18:09:53,819 pg_log]INFO: {'i_status': 1, 'i_port': 8, 'i_index': 8} (test_func.py:97)

[2012-02-12 18:09:53,819 pg_log]INFO: {'i_status': 1, 'i_port': 7, 'i_index': 9} (test_func.py:97)

[2012-02-12 18:09:53,819 pg_log]INFO: {'i_status': 1, 'i_port': 21, 'i_index': 10} (test_func.py:97)

[2012-02-12 18:09:53,819 pg_log]INFO: {'i_status': 1, 'i_port': 23, 'i_index': 11} (test_func.py:97)

[2012-02-12 18:09:53,819 pg_log]INFO: {'i_status': 1, 'i_port': 29, 'i_index': 12} (test_func.py:97)

[2012-02-12 18:09:53,819 pg_log]INFO: {'i_status': 1, 'i_port': 3000, 'i_index': 4} (test_func.py:97)

[2012-02-12 18:09:53,819 pg_log]INFO: {'i_status': 1, 'i_port': 1999, 'i_index': 6} (test_func.py:97)

[2012-02-12 18:09:53,819 pg_log]DEBUG: operate_sqlite3_tbl_product leaving... (test_func.py:101)







3、psql查看结果：





[root@kevin ~]# su - postgres

[postgres@kevin ~]$ psql -U dyx1024 -d kevin_test

psql (8.4.2)

Type "help" for help.



kevin_test=# \dt

        List of relations

 Schema |   Name   | Type |   Owner   

--------+---------------+-------+----------------

 public | tbl_product3 | table | dyx1024

 public | tbl_test_port | table | pg_test_user_3

(2 rows)



kevin_test=# select * from tbl_product3;

 i_index | sv_productname 

---------+----------------

     | apple

(1 row)



kevin_test=# select * from tbl_test_port;

 i_index | i_port | i_status 

---------+--------+----------

    1 |   2 |    1

    2 |   3 |    1

    3 |   5 |    1

    5 |   0 |    1

    7 |   18 |    1

    8 |   8 |    1

    9 |   7 |    1

   10 |   21 |    1

   11 |   23 |    1

   12 |   29 |    1

    4 |  3000 |    1

    6 |  1999 |    1

(12 rows)



kevin_test=# \q

[postgres@kevin ~]$