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@dynacomtm.com rnd@gatewaynet.com
