Re: Understanding Schema's

On Tue, 2010-12-14 at 19:08 -0500, Carlos Mennens wrote:
> I've recently switched from MySQL & have read the documentation for
> 'schema's' however I guess I'm just not at that level or really daft
> when it comes to database design.
>
> http://www.postgresql.org/docs/current/static/ddl-schemas.html
>
> I'm trying to understand the relation between actual databases &
> tables but can't grasp the relation with schema's so I was wondering
> if someone has an easy way of explaining this beyond the documentation
> I linked above. I notice my fresh 9.0 install has a default schema
> called 'public' which every newly database I create defaults to and I
> also created two new schema's called 'fire' & 'ice' but from what I
> have written above, obviously I don't have any understanding of how
> they work.
>
> I greatly appreciate any info and or help since I appear to be lost.

It works like this:

cluster/catalog->[N]_Databases->[N]_Schemas->[N]_Objects

You can cross query a schema but not a database.

So you can create:

create table fire.foo()
create table ice.foo()

And they are isolated from each other physically and logically but you
can query them both:

SELECT fire.*, ice.* join on (id)

(psuedo SQL of course)

Sincerely,

Joshua D. Drake

>
> -Carlos
>

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