Re: Some design issues?

On Sat, 29 Dec 2001 15:33:35 +0000, stu wrote:

> Have a look at the attached picture (I just attached it cause its only
> 32k)

You should use relational algebra instead of any proprietary graphical output that I don't want to look at. :-)

> I am unsure of when to create indexes. If I'm posting a foreign key
> should this be indexed? e.g. UserID in Play List

You will automatically have an index set to your primary key attributes and may optionally put an index on e. g. foreign keys, too. An additional index makes sense if you are going to create complex joins between your tables. The join conditions/restrictions usually depend on a lot of different attributes and you may want to create an index for each and every one of those. It can speed up your queries drastically.  

> I am also unsure about the right hand side of the picture. There seems
> to be a lot of loops (which I'm told are not a good thing).

How would you define the word "loop" in this context? If you are not sure about database design issues, you may want to have a look at some normalisation rules. These rules make sure you are not having a lot of redundant data, or run into trouble when updating/deleting some rows of badly designed tables.

Andi

-- 
Andreas Bauer, baueran at in.tum.de, http://home.in.tum.de/baueran/
"Well, I would describe him as sorta human shape, he's got blue jeans, a
shirt on...." -- Derek in Bad Taste