Basic ERD Question

[jyurkiw]

I'm trying to learn how to properly format Entity Relationship Diagrams in such a way that they're useful to people other than me because I've been forced in the past to develop based on extremely sketchy and poorly organized design documentation. If you've ever had to do that you know how painful it can be and I'm determined to not be one of those guys.

Anyway, I'm starting a "simple" (anything but) project and I want to design it before I start actually coding. Since step one is the database I figured I'd start with the ERD (I think visually so a diagram usually comes before written text).

What I'm looking to find out is if I'm on the right track, in the right ballpark, kind-of doing it right, or if I'm in the vicinity of "run away and light myself on fire before I work with that ERD".

http://i135.photobucket.com/albums/q134/jyurkiw/guildSch.png

The concept behind this "masterpiece" is a piece of software used to organize the schedules of raiders in games such as World of Warcraft (yes...I'm one of those) and comprehensively compare availability in order to find an optimal raiding schedule.

One guild has many raids.
One guild has many raiders.
One raid has many raiders.
One raid has one raid leader.
One raid has one loot master.
A raid leader is a raider.
A loot master is a raider.

A raider may be both a raid leader and a loot master.
A raider may be scheduled for many raids.
A raider may be raid leader for many raids.
A raider may be loot master for many raids.
A raider may be both raid leader and loot master for many raids.

Am I even close?

[olivthill2]

My personal point of view is that Entity Relationship diagrams are beautiful in manuals, but are not very useful. I prefer to have:

- A list of tables sorted by order of importance,
- The fields (columns) making the primary key for each table,
- The fields which are external keys in the case when this is not obvious.

It is also a good point if fields have well chosen names, and tables are designed following the rules of normalizations of E. Codd ( http://en.wikipedia.org/wiki/Database_normalization ).

[davide++]

Hi all.
I've quicly read your post and I saw your ER diagrams, and seems you've caugth the relationships between entities. The only thing I see it's wrong it's Loot Master and Raid Leader entities; they're raiders, so it is unnecessary to add other entities. Instead you should add the attribute Loot Master and Raid Leader to the Raid entity, so you can say who is the loot master and raid lader for each raid.

I hope this will help you.