Re: Advice about a parent-child relation design - Mailing list pgsql-novice

From Felipe Santos
Subject Re: Advice about a parent-child relation design
Date
Msg-id CAPYcRiVWY3TVT1qhmJXoHGM0ELv2iCxd7Ai8AerpSuQg9jCQeg@mail.gmail.com
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In response to Advice about a parent-child relation design  (JORGE MALDONADO <jorgemal1960@gmail.com>)
List pgsql-novice


Em 21/11/2015 3:46 PM, "JORGE MALDONADO" <jorgemal1960@gmail.com> escreveu:
>
> I have 2 tables: parent and child. One of the fields, which should supposedly be part of the parent table, might occassionaly be different for one of the child table records. 
>
> ParentTable
> * id
> * date
> * customer  <-----
> * reference
> * other fields...
>
>
> ChildTable
> * id-parent
> * document type
> * customer  <-----
>
> It is possible that the customer field is not the same for all of the child records. This is a very specific (and strange) situation that might eventually appear in the information system I am developing. I suppose that such a field must be part of the child table even if this case does not appear frequently.
>
> I am writing to ask for your feedback and see if there is another possible approach.
>
> With respect,
> Jorge Maldonado

Hi Jorge,

One question: since the Child table has  the parent  id , why do you need to replicate the customer information ?

Regards

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