Re: [HACKERS] Inheritance, referential integrity and other constraints

From: Chris Bitmead <chris(at)bitmead(dot)com>
To: Oliver Elphick <olly(at)lfix(dot)co(dot)uk>
Cc: pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] Inheritance, referential integrity and other constraints
Date: 2000-01-28 00:10:39
Message-ID: 3890DE7F.5409C776@bitmead.com
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Oliver Elphick wrote:

> No, the inheritance system doesn't allow them to be different types.
> You get an error if you try to create such a table:

Hmm. While it might allow it, I can't see the logic in it. Can't think
of any OO language that thinks this way. All other languages you get
two different variables either with :: scope resolution in C++ or
renaming in Eiffel.

> Because the column names are identical, they are overlaid and treated
> as the same column. This is so whether or not they ultimately derive
> from the same parent, so it isn't strictly a case of repeated inheritance
> as in Eiffel. (There, repeatedly inherited features of the same parent
> are silently combined, but identical names from unrelated classes are
> conflicts.)

Which seems like the right thing to me.

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