RE: [PHP-DB] Concept help required
| From: | Tim Foster | Date: | Wed, 09 Jan 2002 23:02:01 +0000 |
| Subject: | RE: [PHP-DB] Concept help required | ||
| References: | 1 | Groups: | php.db |
| Request: | Send a blank email to php-db+get-15576@lists.php.net to get a copy of this message | ||
You wouldn't happen to have a spare ELH diagram (or two) lying around
that one could take a look at, would you?
Thanks.
TIM
-When you save for a long time to buy something, then you find
that you can't afford it --- that's inflation.
> -----Original Message-----
> From: DL Neil [mailto:PHPml@DandE.HomeChoice.co.uk]
> Sent: Wednesday, January 09, 2002 7:23 AM
> To: George Pitcher; php-db@lists.php.net
> Subject: Re: [PHP-DB] Concept help required
> =The purpose of an ELH diagram is to take a piece of data
> (in your case, because we are assuming/checking
> normalisation, I'd 'cheat' and work at the table level -
> rather than something more atomic like the data-item
> level). Once again we draw boxes (I have some wonderful s/w
> for doing these tasks, but it is M$). A single
> label/box at the top, featuring the name of the data-unit,
> and I would guess a minimum of three (must be my
> favorite number!) boxes in the next row, representing the
> arrival/creation of the data, its use within the
> system, and the removal of the data from the system once
> its usefulness has subsided, respectively. The third
> row of boxes represents the actual, individual events in
> the life-cycle/daily operation of the system, and how
> they alter/update/use the data. Lines drawn between the
> boxes show how these events relate and where there may
> be some iteration.