Message-ID: <3E25F6F0.6030501@klaster.net>
Date: Thu, 16 Jan 2003 01:04:00 +0100
From: Tomasz Myrta <jasiek@klaster.net>
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To: "Ross J. Reedstrom" <reedstrm@rice.edu>
Cc: Matthew Nuzum <cobalt@bearfruit.org>, pgsql-sql@postgresql.org
Subject: Re: lost on self joins
References: <3E25BDAF.8060109@klaster.net>
	<003101c2bcd3$720ab1a0$6700a8c0@mattspc>
	<20030115225444.GB29593@wallace.ece.rice.edu>
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Ross J. Reedstrom wrote:

>>>>Finaly, a table to allow a many to many join called files_folders
>>>>| files_folders
>>>>================
>>>>x| ffid
>>>>| folderid (fk to folders.folderid)
>>>>| fileid (fk to files.fileid)
>>>
>>>Strange. Do you need this table? Can one file exist in several
>>>directories?
>>>If not, you can just add "folderid" field into table files.
>>
>>Good point.  No, it can't exist in multiple folders, so I guess it's
>>overkill to do a many to many here.  Thanks for the moment of clarity.
>
>
>Unless you're attempting to accurately map Unix filesystem sematics, where
>the exact same file _can_ be in more than one place in the filesystem
>(hard links).  It's all about the inode. One of the wierder bits of unix
>that you don't often see used in common occurances.
>
>Ross

If we are talking about Unix filesystems - this solution doesn't 
let you change filename when using hard (symbolic) links.
Anyway I wish I could use symbolic link on windows machine 
the same like on linux one...

I think more important for Matthew would be protection against circular 
join which causes query to hang up.

Tomasz