"Hiroshi Inoue" <Inoue@tpf.co.jp> writes:
>> A database corresponds to a catalog and a schema corresponds to nothing
>> yet.
> Oh I see your point. However I've thought that current PostgreSQL's
> database is an imcomplete SCHEMA and still feel so in reality.
> Catalog per database has been nothing but needless for me from
> the first.
It may be needless for you, but not for everybody ;-).
In my mind the point of the "database" concept is to provide a domain
within which custom datatypes and functions are available. Schemas
will control the visibility of tables, but SQL92 hasn't thought about
controlling visibility of datatypes or functions. So I think we will
still want "database" = "span of applicability of system catalogs"
and multiple databases allowed per installation, even though there may
be schemas subdividing the database(s).
regards, tom lane