Re: A situation with one parent table and 3 child tables

Поиск
Список
Период
Сортировка
От Gareth Evans
Тема Re: A situation with one parent table and 3 child tables
Дата
Msg-id 0C0B8C3D-D729-4916-B105-0FF998D4D2D4@fastmail.fm
обсуждение исходный текст
Ответ на A situation with one parent table and 3 child tables  (JORGE MALDONADO <jorgemal1960@gmail.com>)
Список pgsql-sql
Hi Jorge,

Several 1:m relationships may be appropriate where the number of corresponding records on the m side can be 0, 1 or more.

If the child entities vary little or not at all in structure, but represent different “types”, a single 1:m might suffice with “type” as an attribute at the many end, and suitable indexes, and filtering at the application level.

It's difficult to generalise.  If you can give more information on the scenario, better advice may be forthcoming.

Kind regards,
Gareth


On 2 Oct 2023, at 21:59, JORGE MALDONADO <jorgemal1960@gmail.com> wrote:


Hi,

I have one parent table (table_p) with 3 child tables (table_ch1, table_ch2 and table_ch3). Each record of the parent table can be associated with 1 and only 1 child table records. This means that:

* Some records of the table_p will link to records of table_ch1
* Some records of the table_p will link to records of table_ch2
* Some records of the table_p will link to records of table_ch3

At first look, this does not make very much sense to me. I thought about considering 3 parent tables, one for each child table. However, the 3 parent tables would have the same exact structure and I would like to know if there is a workaround for this issue.

Thanks in advance.

Jorge Maldonado

В списке pgsql-sql по дате отправления:

Предыдущее
От: JORGE MALDONADO
Дата:
Сообщение: A situation with one parent table and 3 child tables
Следующее
От: "David G. Johnston"
Дата:
Сообщение: Re: A situation with one parent table and 3 child tables