Re: Messy data models (Re: Visualize database schema)

On 18/08/12 04:33, David Johnston wrote:
>> -----Original Message-----
>> From: pgsql-general-owner(at)postgresql(dot)org [mailto:pgsql-general-
>> owner(at)postgresql(dot)org] On Behalf Of Wolfgang Keller
>> Sent: Friday, August 17, 2012 9:08 AM
>> To: pgsql-general(at)postgresql(dot)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