Re: some ideas about db rheory

vldm10 wrote:
> On Jul 8, 5:30 am, paul c <toledobythe..._at_oohay.ac> wrote:

>> I doubt if I would get the drift of the rest of your message no matter
>> how hard I tried

Thanks, not sure if I had ever noticed those messages before but if I had I probably would have discounted them as soon as they suggested that dependencies are somehow intrinsic to the question when at most they are only a way to enumerate or differentiate cases (a misleading way if you ask me even though I know Date uses them, maybe that's why he concludes certain updates are 'unsafe'. Apart from that the various 'principles' that he invokes make me uncomfortable because they suggest that some approaches are more 'proper' than others, somehow more 'inherent', when in fact and in the first place there is no inherent insert or delete in   the bare RM. How an implementation language defines the assertion and retraction of facts is closer to a matter of policy than of principle, so I sometimes wish Date would say 'policy of ...', instead of 'principle of ...'. People who want to avoid mysticism need to recognize the place of logic in an rdbms, where it starts and where it ends. When they suggest a language that can retract certain facts but not assert those same facts, or vice-versa, I think their language definitions need some more work, to put it mildly!). Received on Fri Jul 10 2009 - 04:34:28 CEST