Re: object algebra

> The Relational Model treat the relationships between objects in a
> robust mathematical manner.

For even a small collection of things, the number of permutations that they could be related is huge. To deal the complexity, humans have devised various methods. Thus far, RDM has been the most popular because of its robustness and applicability to a large range of applications. RDM, like all methods, imposes rules on the collection of things. On the plus side, the rules make some representations/operations easier and more robust (ie those where data fits neatly in tables). On the minus side, the rules make other representations/operations more difficult (ie trees). The deficiencies of RDM to manage things for some range of applications is why there are OODBs, XML, MV and XDb. XDb is a partial/experimental implementation of TDM. TDM is a more general model than RDM. This is why it can equally manage things arranged as either tables or trees, has OO characteristics, no NULLs, transitive closure and fits on a floppy to boot :) Received on Sat Feb 21 2004 - 01:44:09 CET