Path: news.easynews.com!core-easynews!newsfeed1.easynews.com!easynews.com!easynews!newsfeed1.earthlink.net!newsfeed.earthlink.net!stamper.news.pas.earthlink.net!newsread1.prod.itd.earthlink.net.POSTED!not-for-mail Newsgroups: comp.databases.theory Subject: Re: Do Data Models Need to built on a Mathematical Concept? Reply-To: Anne & Lynn Wheeler References: <17ce58cf.0304240518.34ebfe22@posting.google.com> <4b45d3ad.0305011433.5ae8baa4@posting.google.com> <3EB1AA25.50307@atbusiness.com> <4b45d3ad.0305021419.4226e8b@posting.google.com> <4b45d3ad.0305031919.438d71d2@posting.google.com> From: Anne & Lynn Wheeler In-Reply-To: <4b45d3ad.0305031919.438d71d2@posting.google.com> (neo55592@hotmail.com's message of "3 May 2003 20:19:13 -0700") Message-ID: Organization: Wheeler&Wheeler User-Agent: Gnus/5.090019 (Oort Gnus v0.19) Emacs/21.2 (windows-nt) Cancel-Lock: sha1:0hSam/8CyNGpp/AelZYVHBDh6BM= MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Lines: 39 Date: Sun, 04 May 2003 22:36:07 GMT NNTP-Posting-Host: 165.121.177.222 X-Complaints-To: abuse@earthlink.net X-Trace: newsread1.prod.itd.earthlink.net 1052087767 165.121.177.222 (Sun, 04 May 2003 15:36:07 PDT) NNTP-Posting-Date: Sun, 04 May 2003 15:36:07 PDT Xref: core-easynews comp.databases.theory:26151 X-Received-Date: Sun, 04 May 2003 15:37:38 MST (news.easynews.com) neo55592@hotmail.com (Neo) writes: > Just as in pure set theory, I want the flexibility that the elements > can be anything. But, in the rdb model, that flexibility cannot be > fully realized because the type of values in a domain is restricted > to some hardware dependent type (ie int, long, date, 50 chars, > etc). If I think of a set of arbitrary thing in my mind, I don't > think about their type to decide if they can on cannot be included > in that set. If the things in a set are of different types, I > probably would not be performing operations such as add or average > on them. as an aside fips193, sql standard http://www.itl.nist.gov/fipspubs/193-1.htm ... & from above: SQL is particularly appropriate for the definition and management of data that is structured into repeated occurrences having common data structure definitions. SQL provides a high-level query and update language for set-at-a-time retrieval and update operations, as well as required database management functions for schema and view definition, integrity constraints, schema manipulation, and access control. SQL provides a data manipulation language that is mathematically sound and based on a first-order predicate calculus. SQL is self-describing in the sense that all schema information is queryable through a set of catalog tables called the Information Schema. ... sql from slightly different view: http://www.it.bond.edu.au/inft320/003/lectures/Relational%20Data/node6.html http://www.cis.ohio-state.edu/~gurari/course/cis670/cis670Ch9.html ... & just for kicks, a non-rdb, graph/network model http://www.jfsowa.com/pubs/semnet.htm for arbritrary occuring information, including possibly anomolous and non-regular real-world structures. -- Anne & Lynn Wheeler | http://www.garlic.com/~lynn/ Internet trivia 20th anv http://www.garlic.com/~lynn/rfcietff.htm