[OT] large db question about no joins

Daniel Fetchinson fetchinson at googlemail.com
Fri Apr 17 01:04:17 CEST 2009

>> Hi folks, I've come across many times the claim that 'joins are bad'
>> for large databases because they don't scale.
> I think that means joins with very large result sets and lots of
> different values being matched on between the two tables.  The usual
> use of a join in, say, web server programming, is to look up something
> with just a few results and just one value being matched.  That scales
> pretty well.

Well, on the Google App Engine there is no join either, if I remember
correctly, because it uses bigtable which doesn't support join (if I'm
wrong I'd be happy to be corrected).

So for example on GAE, how would I represent my data of zoos, cages,
animals, legs? Or any other data structure that in a traditional RDBMS
uses joins?


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