Databasen - Revisited

[Matt Sergeant]

On 18-Oct-06, at 11:08 AM, Nigel Rantor wrote:

> So, due to the excellent response to the first post regarding  
> interviewing DB candidates and some of the weird and wonderful  
> ideas they have I present my second, very open, question...
>
> What is your favourite question to guage someone's level of  
> expertise in the database field generally, without reference to any  
> specific DB.
>
> Have at it mongers...

Q: What is wrong with the following setup:

CREATE TABLE Month (
   id INTEGER PRIMARY KEY,
   name VARCHAR(16),
   shortname VARCHAR(3)
);

INSERT INTO Month VALUES (1, "January", "Jan");
...

There are lots of fairly obvious right answers (localisation would be  
one obvious one), but most people won't get the fact that the primary  
key index is a bad thing, because the entire table fits into a single  
page of pretty much every DB I know, so index access is actually  
slower than a full table scan.

If they answer with that, it's an instant hire (though I've never  
given this question to anyone. 9 out of 10 DBAs wouldn't even get it,  
sadly).

Matt.

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