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/' target='_blank'>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 loggingimport logging.configimport 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 loggerdef 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_testpsql (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 ~]$