我相信这是ANSI标准.

实际上，我认为这是SQL-92标准.

该标准的更高版本似乎可以有选择地允许使用128个字符的名称，但是Oracle尚不支持(或允许部分字符支持，因为它允许30个字符.嗯.)

在此页面上搜索"F391，长标识符" ... http://stanford.edu/dept/itss/docs/oracle/10g/server.101/b10759/ap_standard_sql001.htm

(正在寻找参考)

I can understand that many years ago there would be this kind of limitation, but nowadays surely this limit could easily be increased. We have naming conventions for objects, but there is always a case that turns up where we hit this limit - especially in naming foreign keys.

Does anybody actually know why this isn't a bigger size - or is it bigger in 11g?

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Apparently the answer is that it will break currently scripts that aren't defensively coded. I say that is a very worrying thing, Oracle is trying to be the database, surely this is the kind of thing that you must constantly improve, otherwise your product will die the death of a thousand cuts.

Whenever I see this kind of objection in-house, I think it is time to bite the bullet and sort it out. If people are running scripts that they do not check or maintain when they upgrade Oracle versions, then let them suffer the consequences of that choice. Provide them a compatibility flag, up the size to 4000, then save me the wasted time when I'm creating objects of having to constantly count to 30 to check the name is 'OK'.

I believe it's the ANSI standard.

EDIT:

Actually, I think it's the SQL-92 standard.

A later version of the standard appears to optionally allow for 128 character names, but Oracle doesn't yet support this (or has partial support for it, insofar as it allows 30 characters. Hmmm.)

Search for "F391, Long identifiers" on this page... http://stanford.edu/dept/itss/docs/oracle/10g/server.101/b10759/ap_standard_sql001.htm

(Looking for a ref)