ORACLE XE版本的限制

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 in Section 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.