Path: dp-news.maxwell.syr.edu!spool.maxwell.syr.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!postnews.google.com!i3g2000cwc.googlegroups.com!not-for-mail From: "Paul Mansour" Newsgroups: comp.databases.theory Subject: Re: Surrogate Keys: an Implementation Issue Date: 19 Jul 2006 10:06:03 -0700 Organization: http://groups.google.com Lines: 19 Message-ID: <1153328763.419208.135880@i3g2000cwc.googlegroups.com> References: <1153323860.787392.82180@75g2000cwc.googlegroups.com> <1153328021.184233.52920@i3g2000cwc.googlegroups.com> NNTP-Posting-Host: 64.51.54.98 Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-Trace: posting.google.com 1153328768 4530 127.0.0.1 (19 Jul 2006 17:06:08 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Wed, 19 Jul 2006 17:06:08 +0000 (UTC) In-Reply-To: <1153328021.184233.52920@i3g2000cwc.googlegroups.com> User-Agent: G2/0.2 X-HTTP-UserAgent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1),gzip(gfe),gzip(gfe) Complaints-To: groups-abuse@google.com Injection-Info: i3g2000cwc.googlegroups.com; posting-host=64.51.54.98; posting-account=qt_oWAwAAACJcrnjRZCBve-5Tg9Y_h3P Xref: dp-news.maxwell.syr.edu comp.databases.theory:43463 Paul Mansour wrote: > paul c wrote: > > > A system-supplied CANDIDATE key seems no more a bad conclusion than a > > system-supplied date but I suspect there are readers here who would > > prefer to complicate the environment by dragging in various code > > standards or other arbitrary inventions. TTM suggests this very thing > > in its 'RM strong suggestions' and can be found online although the book > > goes into more detail and IIRC avoids using the to me risky word > > 'super'. It also doesn't pre-suppose a '32-bit' value - eg., that > > could have wrap-around problems. Maybe it's another argument for always > > using views at the application level. I forgot to add that 'super primary key' and '32-bit' value were thrown inadvisedly into my original post. Both of these are of course implemention issues, and the Relational Model would certainly be silent on both the concept of an immutable, unexposed identifier and whether or not it should be a 64 bit int or what have you.