Re: Extending my question. Was: The relational model and relational algebra - why did SQL become the industry standard?

>
>
>For what it is worth, from this discussion I am still convinced that bags are
>a bad model for users, because to quote from Date's second article,
>
Thanks for the support, Paul ;-)

>The extra complexity of a bag algebra (even if it only 'a bit' more complex)
>is of no use for users, at least in mine and Chris Date's opinion. Reminds me
>of transactions actually, again possibilities get expanded but not usefully so
>(except maybe for those that teach ;-) ;-) ).
>
Same for GOTO's ;-)

>As an internal bag algebra might well help implementations provide better
>performance, I can see arguments for exposing such an algebra to users to
>possibly make the implementators life easier. However, that is the tail
>wagging the dog. I can only see costs in a bag algebra for users.
>
How does it make implementors life easier? They have to support 'distinct' anyway, don't
they? Well, up to now 'distinct' hasn't been very well supported, so NOT supporting
it has made their life easier, I guess...

regards,
Lauri Pietarinen Received on Sat Feb 15 2003 - 22:51:46 CET