SQL在单个命令中在表中添加列和注释 [英] SQL to add column and comment in table in single command

问题描述

我正在将Oracle 11g用于我的Web应用程序.我想向现有表添加列和注释.我可以使用以下命令轻松做到这一点

I am using Oracle 11g for my web application. I want to add a column and a comment to an existing table. I can do that easily with the below commands

ALTER TABLE product ADD product_description VARCHAR2(20)

和

COMMENT ON COLUMN product.product_description 
     IS 'This is comment for the column';

但是我想在单个命令中完成上述任务.我在互联网上搜索了一个命令，以在单个命令中添加列和注释，但找不到.我想知道这是否可能.任何建议将不胜感激.

But I want to do above task in single command. I searched on internet for a command to add a column and comment in a single command but I couldn't find. I wonder if this is possible. Any suggestions would be highly appreciated.

推荐答案

不，你不能.

没有任何理由需要这样做.这是一次操作，因此只需额外的一两秒钟即可真正键入并执行.

There's no reason why you would need to. This is a one-time operation and so takes only an additional second or two to actually type and execute.

如果您要在Web应用程序中添加列，则这更表明您的数据模型存在缺陷，因为您不需要这样做.

If you're adding columns in your web application this is more indicative of a flaw in your data-model as you shouldn't need to be doing it.

响应您的评论，评论是列属性；它可能似乎，所以Oracle在后台将其存储为 object 的属性.

In response to your comment that a comment is a column attribute; it may seem so but behind the scenes Oracle stores this as an attribute of an object.

SQL> desc sys.com$
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 OBJ#                                      NOT NULL NUMBER
 COL#                                               NUMBER
 COMMENT$                                           VARCHAR2(4000)

SQL>

该列是可选的，sys.col$不包含注释信息.

The column is optional and sys.col$ does not contain comment information.

我不知道，我这样做是为了只有一个处理评论的系统，而不是多个.

I assume, I have no knowledge, that this was done in order to only have one system of dealing with comments rather than multiple.

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