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Re: Arrays Design Question

From: Achilleus Mantzios <rnd(at)gatewaynet(dot)com>
To: josh(at)agliodbs(dot)com
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: Arrays Design Question
Date: 2002-03-27 07:23:32
Message-ID: 02032709233207.09965@pc216 (view raw or flat)
Thread:
Lists: pgsql-sql
On Wednesday 27 March 2002 09:09, you wrote:
> Achilleus ,
>
> > performance for the following problem:
> > I want to store the factors of a linear formula of unknown degree
> >  (but less
> > than 10) in a table for online stats/graphs on historical data (about
> >  200 Mb).
                        ^^^
Dear josh "for" does not mean "in".

> > I am thinking of
> > a) Store each formula as a float8[] array and then write a pgsql
> >  function in C
> > to compute the result given the value of variable x.

Average performer.

> > b) Add 10 columns of type float8 and store 0 values where the
> >  position of the
> > column exceeds the degree of the formula.
>

Worst performer.

The best performer is do the calculations in java using the "arrays" way.
(BTW pgsql Arrays are hated and used by everone it seems)

> BOTH of the above are poor approaches that will lead to headaches for
> you later on.  Instead:
>
> c. Store each formula in a column in another table with a parent-child

           ^^^^ ^^^^^^^    ^ ^^^^^^

That was the question actually.


> relationship to your main table, i.e.
>
> online_stats                           	  stat_formulas
> ---------------                           ------------------
> online_stat_id 		------------->	  online_stat_id
> 					  formula_number
> 				          formula
>
> This is basic relational database design.  You should probably pick up
> a copy of "Relational Database Design for Mere Mortals"  before you
> get yourself into a real mess ...
>
> -Josh Berkus

How did you conclude i was about to store the formulae in the stats table?
Is my English that bad?
:))

-- 
Achilleus Mantzios
S/W Engineer
IT dept
Dynacom Tankers Mngmt
tel:    +30-10-8981112
fax:    +30-10-8981877
email:  it(at)dynacomtm(dot)com
        rnd(at)gatewaynet(dot)com


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