Python:操作PostgreSQL数据库(使用DB API2.0)

   昨天在《Python:操作PostgreSQL数据库(使用PyGreSQL)》一文中使用PyGreSQL模块实现了对PostgreSQL数据库的操作，今天使用另一种python通用的数据库访问接口DB API2.0来实现一下同样的操作，其实在《Python:操作嵌入式数据库SQLite》一文中我们使用的就是DB API2.0，我们可以看到，它对不同数据库提供了统一的访问接口，更多关于DB API2.0的介绍请参考http://www.python.org/dev/peps/pep-0249/

   来看看实现，首先我们要下载提供DB API2.0接口的模块psycopg2,路径：http://initd.org/psycopg/download/，此模块API手册地址为：http://initd.org/psycopg/docs/index.html

一、实现：

#!/usr/bin/env python # -*- coding: utf-8 -*- #导入日志及psycopg2模块 import logging import logging.config import psycopg2 #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:2012-02-13 ''' 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:2012-02-13 ''' pgdb_logger.debug("operate_postgre_tbl_product enter...") #连接数据库 try: pgdb_conn = psycopg2.connect(database = 'kevin_test', user = 'dyx1024', password = '888888', host = '192.168.230.128') 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.") pg_cursor = pgdb_conn.cursor() #删除表 sql_desc = "DROP TABLE IF EXISTS tbl_product3;" try: pg_cursor.execute(sql_desc) except Exception, e: print 'drop table failed' pgdb_logger.error("drop table failed, ret = %s" % e.args[0]) pg_cursor.close() pgdb_conn.close() return pgdb_conn.commit() 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: pg_cursor.execute(sql_desc) except Exception, e: print 'create table failed' pgdb_logger.error("create table failed, ret = %s" % e.args[0]) pg_cursor.close() pgdb_conn.close() return pgdb_conn.commit() pgdb_logger.info("create table(tbl_product3) succ.") #插入记录 sql_desc = "INSERT INTO tbl_product3(sv_productname) values('apple')" try: pg_cursor.execute(sql_desc) except Exception, e: print 'insert record into table failed' pgdb_logger.error("insert record into table failed, ret = %s" % e.args[0]) pg_cursor.close() pgdb_conn.close() return pgdb_conn.commit() pgdb_logger.info("insert record into table(tbl_product3) succ.") #查询表方法一 sql_desc = "select * from tbl_product3" try: pg_cursor.execute(sql_desc) except Exception, e: print 'select record from table tbl_product3 failed' pgdb_logger.error("select record from table tbl_product3 failed, ret = %s" % e.args[0]) pg_cursor.close() pgdb_conn.close() return for row in pg_cursor: print row pgdb_logger.info("%s", row) print '*' * 20 #查询表方法二 sql_desc = "select * from tbl_test_port" try: pg_cursor.execute(sql_desc) except Exception, e: print 'select record from table tbl_test_port failed' pgdb_logger.error("select record from table tbl_test_port failed, ret = %s" % e.args[0]) pg_cursor.close() pgdb_conn.close() return for row in pg_cursor.fetchall(): print row pgdb_logger.info("%s", row) #关闭数据库连接 pg_cursor.close() 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()
二、测试：

1、命令行结果：

(None, 'apple') ******************** (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)
2、日志文件结果：

[2012-02-14 00:12:06,358 pg_log]DEBUG: operate_postgre_tbl_product enter... (db_postgre.py:36) [2012-02-14 00:12:06,453 pg_log]INFO: conntect postgre database(kevin_test) succ. (db_postgre.py:46) [2012-02-14 00:12:06,467 pg_log]INFO: drop table(tbl_product3) succ. (db_postgre.py:62) [2012-02-14 00:12:06,483 pg_log]INFO: create table(tbl_product3) succ. (db_postgre.py:79) [2012-02-14 00:12:06,483 pg_log]INFO: insert record into table(tbl_product3) succ. (db_postgre.py:93) [2012-02-14 00:12:06,483 pg_log]INFO: (None, 'apple') (db_postgre.py:108) [2012-02-14 00:12:06,483 pg_log]INFO: (1, 2, 1) (db_postgre.py:124) [2012-02-14 00:12:06,483 pg_log]INFO: (2, 3, 1) (db_postgre.py:124) [2012-02-14 00:12:06,483 pg_log]INFO: (3, 5, 1) (db_postgre.py:124) [2012-02-14 00:12:06,483 pg_log]INFO: (5, 0, 1) (db_postgre.py:124) [2012-02-14 00:12:06,483 pg_log]INFO: (7, 18, 1) (db_postgre.py:124) [2012-02-14 00:12:06,500 pg_log]INFO: (8, 8, 1) (db_postgre.py:124) [2012-02-14 00:12:06,500 pg_log]INFO: (9, 7, 1) (db_postgre.py:124) [2012-02-14 00:12:06,500 pg_log]INFO: (10, 21, 1) (db_postgre.py:124) [2012-02-14 00:12:06,500 pg_log]INFO: (11, 23, 1) (db_postgre.py:124) [2012-02-14 00:12:06,500 pg_log]INFO: (12, 29, 1) (db_postgre.py:124) [2012-02-14 00:12:06,500 pg_log]INFO: (4, 3000, 1) (db_postgre.py:124) [2012-02-14 00:12:06,500 pg_log]INFO: (6, 1999, 1) (db_postgre.py:124) [2012-02-14 00:12:06,500 pg_log]DEBUG: operate_sqlite3_tbl_product leaving... (db_postgre.py:130)