Re: INHERITS doesn't offer enough functionality

Поиск
Список
Период
Сортировка
От Chris
Тема Re: INHERITS doesn't offer enough functionality
Дата
Msg-id 39F4A9F8.B24C1835@bitmead.com
обсуждение исходный текст
Ответ на Re: INHERITS doesn't offer enough functionality  ("Oliver Elphick" <olly@lfix.co.uk>)
Список pgsql-hackers
Marten Feldtmann wrote:

> > You'll still have to do 6 queries in postgres because it does not return
> > fields in sub-classes.
> 
>  Practically this is not such a big problem as one might think.

>  WHEN you have a persistance framework you tell your framework,
> that every attribut is located (mapped or stored or however you
> may see it) in the superclass and then your top class (table)
> helds all attributes your "lowest" subclass has.

I don't understand what you're saying. There is no query which will
bring back a set of objects of different types without truncating the
sub-class fields. Therefore it's a big problem for persistance
frameworks that use inheritance.

>  I can only tell you, what will be an improvement for me as
> a persistance framework programmer and will not help me.
> 
>  What will not help me:
> 
>  * that the database generates OID
> 
>  * that the database generates "clsss" OID (one may want to
>    have that, because to recognize which table the data
>    comes from..)

You don't seem to be thinking much in terms of an Object Data Management
Group style persistence framework. That's a shame since it's becoming
increasingly important. Sun seems to be endorsing it for Java in some
way too.

> 
>  * special features to solve very special problems
> 
>  What will help me:
> 
>  * all the stuff to reduce the number (!) of queries send
>    to database to get my data
> 
>  * a way to insert VERY quickly a larger amount of data
>    into a table.
> 
>  * a good, speedy database
> 
> Marten


В списке pgsql-hackers по дате отправления:

Предыдущее
От: "Vadim Mikheev"
Дата:
Сообщение: Re: foreign key introduces unnecessary locking ?
Следующее
От: Tom Lane
Дата:
Сообщение: Re: Navigating time-warps in the CVS tree (was re the rule system)