今天开发人员在导数据库的时候遇到这个错误：

@H_403_43@ORA-12952: The request exceeds the maximum allowed database size of 4 GB

查了一下才知道XE版本对数据库有相当大的限制，比如说在10g中用户数据最大为4G,11G中最大为11G,如果超出大小就会报ora-12952/ora-12953的错误，毕竟免费的，不能让你肆无忌弹地用。

这是第一次看到Oracle在技术手段上对license的限制。

官方文档如是说：

10G xe版本的限制：

1. Express Edition is limited to a single instance on any server;
2. Express Edition may be installed on a multiple cpu server,but may only be executed on one processor in any server;
3. Express Edition may only be used to support up to 4GB of user data (not including Express Edition system data);

4. Express Edition may use up to 1 GB RAM of available memory.

Major Changes for Release 11.2

This section summarizes the major changes between Oracle Database XE Release 11.2 and the prevIoUs release (10.2).

The most obvIoUs difference is in the user interface,specifically the Database Home Page,as explained inSection 8.1.

The resource limitations are the same as for Release 10.2,except that you can now store up to11 GB of user data (not including Express Edition system data),as opposed to 4 GB in Release 10.2.

测试如下：

@H_403_43@C:\Documents and Settings\andyleng>set oracle_sid=XE C:\Documents and Settings\andyleng>sqlPLUS "/AS SYSDBA" sql*Plus: Release 10.2.0.1.0 - Production on 星期五 4月 27 16:17:38 2012 Copyright (c) 1982,Oracle. All rights reserved. Connected to: Oracle Database 10g Express Edition Release 10.2.0.1.0 - Production sql> alter database datafile 4 resize 4g ; Database altered. sql> alter database datafile 4 resize 5g ; alter database datafile 4 resize 5g * ERROR at line 1: ORA-12952: The request exceeds the maximum allowed database size of 4 GB