Re: Failure Modes and Ranges of Operation

Bob Badour <bbadour_at_pei.sympatico.ca> wrote:

>Bob Badour wrote:
>
>> Failure mode analysis is very important in engineering. I wonder whether
>> it has any supporting theory? Certainly, one can think of general
>> principles. Likewise, beyond statistical analysis and empirical
>> measurement, does any theory exist regarding ranges of operation?
>>
>> Any thoughts?
>
>It occurs to me that naive and ill-considered solutions actually
>discourage proper failure mode analysis. SQL and NULL demonstrate this
>clearly.
>
>It seems the SQL folks used NULL as a crutch to avoid thinking about
>important issues. For example, consider all the places where SQL returns
>NULL when we know that is just plain wrong and where a perfectly valid,
>correct answer exists: e.g. summation over zero elements.

     I got bit by this not too long ago. I am not happy. It makes YA thing to check when writing SQL.

>It strikes me the SQL folks probably mistook summation over zero
>elements for a failure condition and had fallen into the habit of
>substituting NULL for thought when it comes to failure modes. Regardless
>what some may believe, no rational justification exists to equate
>divison by zero with NULL, and yet SQL does it.

     There is that, too?

Sincerely,

Gene Wirchenko

Computerese Irregular Verb Conjugation:

     I have preferences.
     You have biases.
     He/She has prejudices.