Here's Tom Lane's response to my original post on pgsql-sql:

> This seems to have considerable overlap with the problem of indexing
> inheritance hierarchies (so that constraints on tables with children
> would work as people expect).  It may be that it's sufficient to solve
> it for inheritance cases, and not try to support the generic case of
> constraints applied across arbitrary sets of tables.  ISTM that the
> latter could introduce a bunch of extra definitional and practical
> issues beyond what you'd have to solve to do the former.
>
> You're discussing it on the wrong list though --- try -hackers.

Hadn't thought of distributed keys being related to inheritance, though 
now I can see how one might apply inheritance to the situations I 
mentioned above. Is this what you were thinking, Tom?

Case 1:

employees (id, name)
schools (name, location)

teachers (id, name, school_name)
	where (id, name) inherits from employees and school_name references 
schools(name)
subs (id, name) inherits from employees
managers (id, name, school_name)
	where (id, name) inherits from employees and school_name references 
schools(name)

Case 3

comments (comment_id, comment)
employees(id, name)
comments_nonemployees (comment_id, comment, name)
	where (id, comment) inherits from comments
comments_employees (comment_id, comment, employee_id)
	where (comment_id,comment) inherits from comments, employee_id 
references employees(id)

  I don't know very much about inheritance in PostgreSQL, so I'm doing a 
bit of reading via Google. If anyone has recommendations on good 
sources re: inheritance in PostgreSQL, I'd be thankful.

Regards,

Michael Glaesemann
grzm myrealbox com


Wed, 24 Dec 2003 13:23:52 -0600
Michael Glaesemann <grzm@myrealbox.com>
Distributed keys / Inheritance