Re: XQuery (and XML) vs LISP

Christopher Browne <cbbrowne_at_acm.org> wrote:

>The trouble is that relations require taking something of a "set"
>perspective, and if facts aren't being expressed that way naturally,
>well, down that road lies some ghastlyness :-).

The thing that has bothered me is that those promoting the relational model typically provide worthless examples, typically employee and department, and seem to almost religiously avoid non-trivial working examples, particularly those that might seem problematic for the scheme.

For example, what is a type? What goes in the 'set', as you express it, never mind any particular domain? Why is a book a 'type', when there are various sorts of books? Why is a chapter a 'type', when the chapters in the same book might be of a very different sort? Is the appendix which is more an index a type to itself? And so on. Are the paragraphs a 'type', and is the paragraph in chapter 4 different than the paragraph entities in relation chapter 5? To normalize things does it require literally hundreds and hundreds of 'relations'/tables to represent the structure? Just think of the 'joins'. And wasn't the RM intended to free people from the 'tyranny of structure'? Received on Sun Feb 05 2006 - 18:22:40 CET