Re: one big tables vs. many smaller

Much like other things in life ... size has nothing to do with it ... it is what you do with it that counts. The definition of a table should be based on data normalization tempered by performance. If it belongs in one table ... stick it there. If not ... don't.

Daniel Morgan

Steffen Ramlow wrote:

> what r the advantages / disadvantages of this?
>
> sample:
>
> Main (pk, id, c1, c2)
> Sub1 (pk1, fk1, c10, c11)
> Sub2 (pk2, fk2, c20, c21)
>
> rows:
>
> Main: 1,1,2,3
> Sub1: 1,1,4,5
> Sub2: 1,1,6,7
>
> vs.
>
> BigMain(pk,id,c1,c2,c10,c11,c20,c21)
>
> rows:
>
> 1,1,2,3,4,5,null,null
> 2,1,2,3,null,null,6,7
>
> the rows are always read as when Main and Subx would be inner joined
>
> obvious is, that BigMain has many null values (there are up to 10 sub
> tables) but u do not need to join Main and Subx
>
> i would use Main + Sub, coz it is better to maintain and to tune, but what
> about the costs of the join?
>
> both tables may contain millions of rows
>
> what r ur options?
Received on Thu Apr 04 2002 - 11:05:37 CST