Re: Serial, concurrent, parallel

On 1/17/2025 1:50 PM, Don Y wrote:

It will also ensure that multistep operations all happen
as an indivisible (atomic) "transaction" so no other
user (accessing the database at that same instant)
will ever see "partial results".  E.g., adjusting the
population of locality 5 down by 321 souls to reflect the
folks who have RELOCATED to locality 88 (you will never
see 321 *extra* people nor 88 *fewer* people, depending

s/88/321/

on the order in which the *individual* population counts
were "adjusted".)

I.e., I can:
    adjust the population of locality 5 down by 321
    THEN, adjust the poulation of locality 88 *up* by 321
OR
    adjust the population of locality 88 up by 321
    THEN, adjust the population of locality 5 down by 321
If <someone> peeks at this data between the first "step"
and the second, they will either see 321 fewer people
living in the country (!) or 321 *more* -- when the
total population hasn't actually changed (as is evident
before and after the "transaction")