问两个关于数据的初级问题

Question

我有两了初级问题，想请教一下大家：

1、我建了一张表后，比如叫 customer，可以用 alter table 增加和修改 column，不过却不能drop它们，删的时候，就提示说ORA-12988: 无法删除属于 SYS 的表中的列，请问是怎么回事。

2、我的 OracleManagerManagementServer 服务很奇怪，我启动以后，过段时间它会自动停止？我也不知道是为什么？

Answer 1

应该是：

alter table customer set unused (tex_exempt_ind);

Answer 2

你是在sys 下创建的 table?

Answer 3

alter table customer set unused column tax_exempt_ind ;

ORA-12988: 无法删除属于 SYS 的表中的列

Answer 4

1。Marking Columns in a Table as Unused

Alter table dbatest set unused ( c_name );

2。Dropping a column or UnUsed Column from a Table

Alter table dbatest drop column ( c9 );

Answer 5

Error:        ORA-12988

Text:        cannot drop column from table owned by SYS

---------------------------------------------------------------------------

Cause:        An attempt was made to drop a column from a system table.

Action:        This action is not allowed

.

Have u solved it? give us your result!

Answer 6

你不能drop column,你可以查看一下你的参数compatible，必须在8.1.0以上。

Answer 7

alter table **

drop column **

cascade constraints

or you may:

alter table **

set unused column **

Answer 8

i can drop table ,but can't drop column;

my memory is 512.

Answer 9

1. in 8i, there is new function that allow you to disable(hide)  columns. please search itpub.

2. I have met this before, personally i think that is because your memory.

good luck!