On 18/08/12 04:33, David Johnston wrote:
-----Original Message-----
From: pgsql-general-owner@postgresql.org [mailto:pgsql-general-
owner@postgresql.org] On Behalf Of Wolfgang Keller
Sent: Friday, August 17, 2012 9:08 AM
To: pgsql-general@postgresql.org
Subject: Messy data models (Re: [GENERAL] Visualize database schema)
[...]
Also, in some models, there are relations that are so prevalent that
including all them just adds noise to the layout when a top-level
description would be just as clear and remove the extra lines from the
graph. How to code a pure layout algorithm to be able to identify those
situations (with our without a standard naming scheme to help it) and create
meaningful "text summaries" while removing the corresponding paths I do not
know but it would also go a long way toward visually simplifying complex
models.
David J.
[...]
I agree with almost all of what David wrote, but I particularly want to reinforce what he says in the last paragraph above.
For example, a lot of tables may have multiple comments associated with individual rows. Since each comment will have a userid, date/time stamp, and text – they will be stored in the own table and referenced via a foreign key. Drawing lines from each affected table to the Comment table would add a lot of clutter with negligible gain.
Similarly, if access to rows in a particular table (and many tables were affected) depended on the company a user belonged to, then this would also add lots of lines...
Cheers,
Gavin