[AccessD] Math equations

 Hi John --

Quick hint: eval(...) and maybe also 'Strategy Pattern' ( http://smsconsulting.spb.ru/shamil_s/patterns/calc/index.htm ) - google for the more details of the latter....

Thank you.

-- Shamil


Среда, 20 марта 2013, 23:16 -04:00 от John W Colby <jwcolby at gmail.com>:
>Does anyone know a way to implement "dynamic" math equations in Access?  I am implementing a system 
>for building up strings of verbiage for mail merge letters.  The verbiage is dependent on the 
>insurer of a loan and the state that the loan is in.  For example it might say something like
>
>"Please Bid $X."  X is the result of an equation that may be something like
>
>X = the greater of FMV or MakeWhole but X must be at least 2/3 TotalDebt.
>
>Or it may say something like X = Y% * FMV or TotalDebt whichever is less, where Y% comes from the 
>insurer table, i.e. Y is 80% for insurer A, 90% for insurerB and 100a% for InsurerC.
>
>The equations can depend on the state but also a % figure taken from the insurer.
>
>There are 51 states and 5 insurers so there are a ton of possible combinations / equations.  All of 
>which comes from a spreradsheet of text "descriptions" for each insurer for each state which I am 
>supposed to somehow compute.
>
>The old system just used a slew of hard coded equations in huge iif() statements, embedded directly 
>in fields in queries.
>
>ICK!
>
>I would prefer to somehow map this to a small(er)  set of equations with values fed in from the 
>state and insurer tables.  The verbiage strings would be stored in the state table, possibly a 
>state/insurer table. where the verbiage is in the table with replaceable symbols in the string.  I 
>could pull the string out of the table, look for X and run a math function to figure out X and 
>substitute the literal X (or other "replaceable character" ) with some dollar amount.
>
>And finally I would like to avoid VBA code if possible.  The intent is to eventually move these out 
>of Access so if the solution mapped easily into C# that would be good.
>
>I have never really seen anything like this implemented (table driven) and I am drawing a blank on 
>how to go about it, particularly without resorting to custom VBA functions.  In the end VBA 
>functions are preferable to IIF() statements in custom Access queries.  I could at least "port" VBA 
>to C# later.
>
>-- 
>John W. Colby
>
>Reality is what refuses to go away
>when you do not believe in it
>
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