how to create data on the fly?

Hello!

i am again struggling with a problem i am unsure how to set up. I could
easily solve all in the php backend, but this would impede further extensions
and doesn't satisfy my curiosity :D

so, here's the problem: a patient takes everyday a medecine, and from time to
time comes in a result of a blood-sample.

Now i first of all, i want to draw a graph showing the dosis taken, and the
blood-values mesured. Later on i want to calculate the assimilation rate, the
saturation rate, and the effective rate, both in real, and prognosis....

My actual problem beeing that the dosis may be not simply 1 to n pills per day,
but for example day 1 1, day 2 1.25, day 3 .5, day 4 1, etc... the most
complex case to now i, has a period over 4 days....

so i set up:

CREATE TABLE patients (
id integer NOT NULL,
name text,
minzone real,
maxzone real,
refresh integer
);

CREATE TABLE inrdata (
id integer NOT NULL,
temps timestamp without time zone,
patid integer,
inr real
);

CREATE TABLE posologie (
id integer NOT NULL,
inrid integer,
champ text,
definition text,
valeur real
);

In patients i have the persons name, and the boundaries that are wanted for
the blood-sample value, in inrdata i have the timepoints where i get a
blood-sample-result, and i eventually adjust the posology.

in posologie i have the table at a timepoint i have stored at the moment in
champ=sequence, definition="1;1.25;0.5;1",

and actually i solve the problem with the frontend....

what i would like is to store the posology iterations in the posology table,
and be able to make a select that generates the data on the fly. Taking
the different waypoints given by the data in inrdata as starting point
and computing for each day the actual dosis....

but i have no idea how to do this in sql?

any help appreciated!

ciao Bruno
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bboett(at)adlp(dot)org