Re: How do you illustrate a database?

[Yvonne deGraw <yvonne -at- SHARK -dot- SMARTSTAR -dot- COM>]

This is getting a bit more "technical" than "writing", but

Steven Owens <uso01 -at- MAILHOST -dot- UNIDATA -dot- COM> asks:

> Hm... I have a feeling I should know what you're referring to here (entity
> relationship diagrams) but I can't place it.  Could you provide a little more
> description?  How about some references to database design books that might
> describe this?

Charles Fisher suggested Edward Yourdon's book, _Modern_Structured_Analysis_,
and James Martin and Carma McClure's _Diagramming_Techniques_for_Analysts_
and_Programmers_.

A relational-database-specific book with examples is:
_Handbook_of_Ralational_Database_Design_ by Candace C. Fleming and Barbara
von Halle. (1989, Addison-Wesley, ISBM 0-201-11434-8).

A simple example (ignore if you don't care about relational databases):

Employee                             Job
---------------                      -------------
| Emp_Num     |           |----------| Job_Class |
---------------           |          -------------
| Name        |           |          | Title     |
| Soc_Sec_Num | assigned  |          | Sal_Min   |
| Job_Class   |<-<--------|          | Sal_Max   |
| Dept_Num    |    (1:20)            | ...       |
| ...         |                      -------------
---------------
The table name goes over the box. The "primary key" fields for each table go
in the top portion of the box. The other fields go in the lower portion.
An arrow points from the primary key to the foreign key that references it.
The relationship (and sometimes a guesstimate of the record ratio) is included
along the arrow. On second thought, I'd probably put the Job table on the
left, but my editor doesn't cut blocks of text that way (wouldn't that be a
nice editor feature...).

-- Yvonne DeGraw
SmartStar Corporation
yvonne -at- shark -dot- smartstar -dot- com