Re: indexes

Tom,

If the real-world primary key is large (say up to 100 characters in length)
> then
> the disadvantage is that you are duplicating this referenced key in
> several
> other tables, each element taking up 100 characters. Space is wasted when
> compared to int4 ID's. But not really sure if this is a performance
> problem for
> SELECT except for the space required (varchar(128) vs. int4).
>

What is worth a try is to check an md5 or sha hash of those 100chars and use
that as a key.

with a proper hashing algorythm (proper= fitting to your data) collisions
should not happen; and you have a shorter key to connect the tables.

best wishes

harald

--
GHUM Harald Massa
persuadere et programmare
Harald Armin Massa
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70197 Stuttgart
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