Python:操作PostgreSQL数据库(使用PyGreSQL)

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昨天使用python写了操作嵌入式数据库SQLite的方法，今天用python写了针对个人比较熟悉的开源数据库PostgreSQL的常用操作，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/

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：

a. 如果跳过以上两步，在import pg时将会报错，浪费较长时间才搞定。

b. 如果对PostgreSQL安装和配置不熟悉，请参考本博客中以下几篇文章：

《RedHat Linux上安装PostgreSQL》

《PostgreSQL服务端监听设置及客户端连接方法》

《PostgreSQL数据库创建、删除方法》

更多PostgreSQL相关知识请访问从我的博客专栏：PostgreSQL系列

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 ~]$