Re: Do Data Models Need to built on a Mathematical Concept?

neo55592_at_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