Re: Lookup tables

On Tue, Feb 4, 2025 at 12:05 PM Rob Sargent <robjsargent(at)gmail(dot)com> wrote:

>
>
>
> On 2/4/25 10:03, Ron Johnson wrote:
>
> On Tue, Feb 4, 2025 at 11:31 AM Michał Kłeczek <michal(at)kleczek(dot)org> wrote:
> [snip]
>
>>
>> The query to register a visit is:
>> insert into restaurant_visit
>> select $user, current_date, restaurant_id, $rating
>> from restaurant where name = $restaurant_name
>>
>>
>> It is now completely unclear what it means to change the name of the
>> restaurant for already registered visits.
>> Is it still the same restaurant with a different name or a different
>> restaurant?
>>
>> Or let say someone swaps names of two restaurants.
>> That means a user that goes to the same restaurant every day would
>> register visits to two different restaurants!
>>
>
> Valid concerns, which means that you add a new restaurant record when the
> name changes.
>
> And there goes your unique index on phone number :)
>

I don't think I'd ever do that, since phone numbers can get reassigned.

Capital-L Large and old businesses probably don't even have unique indices
on SSN.

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