On Sun, Sep 11, 2005 at 11:00:02PM -0800, Poul Jensen wrote:
Tom Lane wrote:
No, tableoid is sort of a virtual column ... it doesn't exist on disk.
When you query it you get a value fetched from the internal data
structure representing the table.
So virtual columns are possible - THIS
Thank you for your input! Individual replies follow below.
##
Chris Travers wrote:
Ok. Imagine two huge huge tables:
file_dataand additional_data
create_table file_data (
file_id serial primary key,
station_id text,
);
create table
Hmm, in fact if the redundant values you're worried about come in
long stretches (e.g., temperature is the same for many observations
in a row), I suppose you could do the same thing - map a constant
value to the range of observation IDs for which it holds. This gets
back to having many
Thank you, John!
I misunderstood you the first time, but I now see we have the same thing
in mind.
So you'd have most of your data in a main table:
create table observations (
obsIDintegerprimary key,-- Maybe a BIGINT
temperaturefloat,
etc.
);
and
That is exactly what I want, and now I finally see how to do it (I
think!). However, it is a considerable amount of work to set this up
manually, plus, it has been a headache realizing how to get there at
all. I'm hoping that one or more of the developers think it would be a
good idea for
To store the detailed records the SQL novice would construct one table
pr. file and exclude any constant columns since these are redundant
(given in summary table). These detailed tables would then have
different column schemas - (mn,tmp,wind) for ~58%, (hr,mn,tmp,wind)
for ~40%,
On Thu, Sep 08, 2005 at 07:58:55PM -0800, Poul Jensen wrote:
This novice must be missing a sneaky way to avoid massive redundancy and
still maintain easy access. I've been suggested to look at inheritance
and foreign keys. Foreign keys I don't see how to use, but I could make
What you seem
I have ~500,000 data files each containing ~1,000 records that I want to
put into a database for easy access.
Fictive example for illustration: File w. meteorological data from a
given station.
stat_id | yr | d_o_y | hr | mn | tmp | wind
-|--|---|||--|--
On Thu, Sep 08, 2005 at 19:58:55 -0800,
Poul Jensen [EMAIL PROTECTED] wrote:
This novice must be missing a sneaky way to avoid massive redundancy and
still maintain easy access. I've been suggested to look at inheritance
and foreign keys. Foreign keys I don't see how to use, but I could
Poul Jensen [EMAIL PROTECTED] writes:
One thought: PostgreSQL adds to every table a system column tableoid
containing a constant value. Is that value really stored 1,000 times for
a 1,000-row table? Or...?
No, tableoid is sort of a virtual column ... it doesn't exist on disk.
When you query
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