Fw: How to FindNearest

I guess I explained that very poorly. Sorry. It is actually much simplier.

I have 3 tables

Hole
Hole_id
X
Y
Z

Down_hole_survey
Hole_id
Depth_meters
Azimuth
Vertical_inclination
X
Y
Z

Sample
Hole_id
Depth_meters
X
Y
Z

Hole_id is a primary key in the hole table while it is a foriegn key in down_hole_survey and sample tables.

My function will take all the above info about the hole and down_hole_survey tables, and sample.hole_id and sample.depth_meters and will calculate the coordinates. I need to put these coordinates into sample.x , sample.y and sample.z .

What I used to do was have one function that would return 3 values (x,y,z). Then create 3 more functions that would call call the main function and pull out the 3 values seperately to update the 3 seperate columns. It works fine but I have to call the main function 3 times which produces a slow performance.

I hope that I explained it better this time.

Phil
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-----Original Message-----
From: Bruno Wolff III <bruno(at)wolff(dot)to>
Date: Tue, 3 Oct 2006 12:11:25
To:Alexander Ilyin <a_ilyin(at)ukr(dot)net>
Cc:pgsql-sql(at)postgresql(dot)org
Subject: Re: [SQL] How to FindNearest

On Tue, Oct 03, 2006 at 14:43:40 +0300,
Alexander Ilyin <a_ilyin(at)ukr(dot)net> wrote:
>
> Thank you for your great idea. But how it can be used for positioning the cursor in the already existed ResultSet? Using your idea I can found the closest to targetvalue row but not its position in my ResultSet.

You wouldn't be able to use it to position a cursor. But if you aren't
retrieving a lot of records at once, this may still be a workable strategy
for you.

> Anyway thank you for your idea it is very useful by itself. Also I can solve my problem using your idea and emulating the movement in my existed ResultSet. Even better - no need to store the large RS between cursor movements. Just each time I need to fetch the all visible rows.

That sounds pretty reasonable.

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