[thelist] SQL help - I think JOINing is required

[Andrew Forsberg]

>=if they are 1-1 relationships, consider putting all the columns into one
>table next time you design tables like this -- there is a performance
>tradeoff, but it's probably immaterial unless you have millions of records,
>but on the other hand, it's easier to write queries against one table than
>four

Hi Rudy

This is interesting. A little while back I took a few online courses 
in Oracle DB design / admin. I don't use Oracle, at the moment, but 
thought it a useful thing to be at least familiar with. One of the 
most alarming things in the course, for me, was the subject of 
database normalisation. It only covered the first three rules (don't 
ask me to cite them... (: ), all of which made sense to me, and 
addressed design problems which I'm confident I would have dealt with 
without knowing the letter of the rules themselves.

That said: in Marc's case these tables are all, at the moment, 1 to 
1. There may be another table sometime in the future that introduces 
a 1 to many relationship off general.ID. Would you work on a 'it's 1 
to 1 at the moment, so stick them in a single table' premise (I'm 
thinking of the problem of data redundancy here, in particular)? or, 
use the current four table solution so future use of the General.ID 
for 1 to many selects is more efficient?

As a *very* highly experienced db designer, do you pay a lot of 
attention to the rules of normalisation, or are you more likely to 
analyze a 'real-world' use and scope of the database? How much 
emphasis would you put on separating out data into different tables 
when it's not strictly-speaking dependant on the key?

I'm honestly not trying to be a smart-arse -- I'm just wary of my own 
'little bit of knowledge is a dangerous thing' scenario. In short: is 
database normalisation a religious process: a faith, or one that 
you're more than happy to override as necessary?

Thanks
Andrew

-- 
Andrew Forsberg
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