Re: Design approaches about primary key

On 27 Nov 2003, domenicg_at_hotmail.com wrote:

> Using meaningless keys when meaningful ones exist is stupid
> because you create a condition that always requires a join to
> pick up the value that everyone understands.

Basing one's keys on the whims of someone else's data storage is dangerous.

> Bad design -- it comes from people copying textbook examples
> and using them in real life.

No, it comes from people creating a database from scratch. Remember, a meaningful key was, on its conception, a meaningless key to someone else.

> My social security number is a key,

It isn't guaranteed to be unique, and it certainly had no meaning on its creation for you.

> so is my phone number (for a telco)

So, what happens when I ask them to change my number to an unlisted one?

> -- they don't assign a sequential number on top of that.

I don't know how telco's design their database's but I'd bet they all look a bit different.

-- 
Galen Boyer