Re: Tables cities and table user

From: The Natural Philosopher <tnp_at_invalid.invalid>
Date: Sun, 10 Feb 2019 11:31:17 +0000
Message-ID: <q3p225$4up$2_at_dont-email.me>

On 09/02/2019 11:21, Chris Elvidge wrote:

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

>> On 09/02/2019 09:50, ^Bart wrote:
>>>> SELECT id_city,name,'IT' from cities_it
>>>> union all
>>>> SELECT id_city,name,'UK' from cities_uk
>>>
>>> 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?
> 
> 

They have pointers to different countries of course.

-- 
The New Left are the people they warned you about.

Received on Sun Feb 10 2019 - 12:31:17 CET