# Re: Who yields - client or developer? Your opinion

From: Tom Ellison <tellison_at_jcdoyle.com>
Date: Wed, 22 May 2002 16:27:05 -0500
Message-ID: <3CEC0D29.7AABA597_at_jcdoyle.com>

In this case, it's not all that bad. Choose one standard unit of measure, perhaps L/Sq.m. Put this and all other units of measure the client wants to use in a single column of a table for "UnitsOfMeasure". In a second column, put a complete conversion formula by which get L/Sq.m. given some value for the area, say a variable named "MeasuredUnits", such as:

UnitsOfMeasure Formula

```L/Sq.m                  MeasuredUnits
Sq.m/L                  1 / MeasuredUnits
kg/Sq.m                 MeasuredUnits * LitersPerKg

```

You may need additional conversion factors such as the LitersPerKg above in order to be able to make the conversion. If you don't have them, then you must leave the result in Kg instead of L. If so, add another column to the table that shows the units of the result.

Even though the Formula is a string, you can Eval(Formula) to get the number you need. It will use the value in the variable "MeasuredUnits" and do the calculation. Pretty neat, huh?

Now you and the client can both be right. Don't forget, the computer is there so they don't have to use their calculators. In fact, if you ask them, you'll find out it's there so they don't have to use their brains, either, but that's another story.

Tom Ellison
Microsoft Access MVP

Graham Bellamy wrote:

> I want to receive application rate in a data field (eg. L/Sq.m). There are various forms
> of this rate, but ultimately I want to multiply it by the area to find the volume. The
> user reads this value from the label of the bottle. But sometimes the rate is written as
> Sq.m/L (how many square meters will 1L cover), in which case I would have to divide by the
> area.
>
> What is more recommended? Design the db such that it can decipher which form the rate is
> being input, which for me (bit of a rookie) would be quite a headache. Or require that the
> user does a simple inversion calculation on his hand calculator (or I could make a little
> form for him, so he still doesn't have to think) and enters that value, in which case any
> future reporting will show the value in L/Sq.m and not what is written on SOME of the
> bottles? I guess this last point (report display) is my main concern.
>
> Note: In my particular situation the rate could also be kg/Sq.m, kg/Sq.m/mm, Sq.m/kg,
> L/Sq.m/mm, as well as the L/Sq.m and Sq.m/L
>
> TIA
> Graham
Received on Wed May 22 2002 - 23:27:05 CEST

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