Re: Tables cities and table user

From: Chris Elvidge <chris_at_mshome.net>
Date: Sat, 9 Feb 2019 11:21:12 +0000
Message-ID: <q3md3a$v7o$1_at_dont-email.me>


On 09/02/2019 10:51, The Natural Philosopher wrote:
> On 09/02/2019 09:50, ^Bart wrote:

[Quoted] >>> SELECT id_city,name,'IT' from cities_it
>>> union all
>>> SELECT id_city,name,'UK' from cities_uk
>>
[Quoted] >> I didn't understand what happen in the cities table when you use the 
>> union all command...
>>
>>> or, even better (before someone else askes this question):
>>> Why do you have mulitple tables with city names?
>>
>> Because I think to store all cities from more or less ten countries or 
>> the entire world it's too heavy to to it just in one table!
>>

>
> I dont think so.
>
> You need a table of countries and a table of cities.
>
> In the city record you have a field that points to the country unique ID
>
> If you are worried about lookup speed, index it
>
>
>> ^Bart
>>

>
>

Ah, but how do you differentiate between (e.g.) London, UK and London, Ontario, Canada? St Petersburg, Russia and St Petersburg, Florida, USA?

-- 

Chris Elvidge, England
Received on Sat Feb 09 2019 - 12:21:12 CET

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