Re: When to use integer keys?

On Jan 23, 7:12 pm, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
>
> What predicates does one want to express relative to BlockType?

IsBlockOfType(BlockA,Type1)

> Do rows
> in the BlockType table do anything other than state that a block type
> exists?

A row in the BlockType table just says that that type is a valid type.

> Do you have referential integrity constraints related to block type?
>

Each block should have a type, but a type can exist without a block of that type. I'm not sure what should happen if a type is deleted. That's unlikely to happen; however, if a BlockType is renamed, that change should apply to all blocks of that type.

> Once you answer those, if you decide you need a BlockTypes table, the
> design criteria for candidate keys are uniqueness, stability,
> familiarity and simplicity.
>
> In my opinion, a character string is as simple as an integer. Are the
> block type names unique, stable and familiar?

The block type names are unique, mostly stable (most will not ever change; a few may change but rarely). They are also familiar.

So please correct me. I know very little about designing databases but it seems that most of my answers point to BlockType just being one column and not a separate table except for the fact that BlockType names may change. Received on Wed Jan 24 2007 - 20:30:43 CET