Обсуждение: Re: Is a better way to have the same result of this

Tomasz,

I am under the impression that a primary key field is automically as a unique index. It seems to be correct after I
verifyit  
with the page http://www.commandprompt.com/ppbook/index.lxp?lxpwrap=c13329%2ehtm#CREATINGANINDEX

Thanks for bringing up the question.

Vernon

12/5/2002 12:35:36 PM, Tomasz Myrta <jasiek@klaster.net> wrote:

>Vernon Wu wrote:
>
>> The personid is a foreign key in the block table, and the the userid
>> is the key of the profile table. So, both are indexed
>> by nature (if I don't make a mistake).
>
>What kind of nature? Did you create indexes for these fields? Postgres
>doesn't create indexes by itself - even if field is a primary key. You
>have to do it on your own. I think also, that Postgres doesn't use index
>for tables having less then 200 rows - sequence scan is faster.
>Regards,
>Tomasz Myrta
>
>
>

Vernon Wu wrote:

> Tomasz,
>
> I am under the impression that a primary key field is automically as a
> unique index. It seems to be correct after I verify it
> with the page
> http://www.commandprompt.com/ppbook/index.lxp?lxpwrap=c13329%2ehtm#CREATINGANINDEX

You are right. Primary key creates unique index. I use sometimes Pgadmin
and it doesn't show these indexes :-(
Tomasz Myrta