Re: Primary keys and composite unique keys(basic question)

On 4/7/21 11:35 AM, Rob Sargent wrote:
>
>> On Apr 7, 2021, at 10:17 AM, Ron <ronljohnsonjr(at)gmail(dot)com> wrote:
>>
>>  On 4/5/21 9:37 PM, Rob Sargent wrote:
>>>> It's a small thing, but UUIDs are absolutely not memorizable by
>>>> humans; they have zero semantic value.  Sequential numeric identifiers
>>>> are generally easier to transpose and the value gives some clues to
>>>> its age (of course, in security contexts this can be a downside).
>>>>
>>> I take the above as a definite plus.  Spent too much of my life
>>> correcting others’ use of “remembered” id’s that just happened to
>>> perfectly match the wrong thing.
>>
>> People seem to have stopped appending check digits to identifiers about
>> 20 years ago, and I'm not sure why.
>>
> No the problem is “start from one”. User has item/I’d 10875 in hand and
> types in 10785 which of course in a sequence supplied ID steam is
> perfectly valid and wrong.  Really hard to track down.

That's my point.  Adding a check digit (turning 10875 into 108753) would
have caught that, since 107853 does not match 107854 (which is 10785 with a
check digit added).

--
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