Re: [OT] lines in ER diagrams

[dialist <pvspam-dialist hacklab net>]

On Wed, 2003-04-23 at 16:02, James K. Lowden wrote:
> You may have senstive data in one of the two tables.  Permissions are
> easier to manage per table than per column.

Aaaah! Finally, 1-->1 makes sense!

The other reasons you cited make me grumble: "Why are we still using
80's vintage RDBMSs?" But this one sounds good (okay, the replication
one sounds plausible, too). Per-column permissions are very
administration heavy, but splitting sensitive columns into other tables
sounds elegant and understandable to me.

I still don't grasp 0-->1 relationships, though. Unless we're saying
somehow you must always query these tables using an outer join.

And 1-->1 vs 1-->1andonly1 seems... equivalent.

-- 
Tim Ellis
Senior Database Architect and author, tedia2sql (http://tedia2sql.tigris.org)
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