Calculating NPV

Question

Dear all,
I get some large amount of data through a batch process from mainframe. I need to calculate NPV (Net Present Value), once per day. When I was searching through sites and posted in some other forums, I could get two replies
1) Use OLAP DML to calculate npv.
How should I do this? I understand that I cannot use an OLAP function just like a select clause. And another point, how will I trigger this every day certain time (like a unix cron)? Please give some links.
2) The spreadsheet technique:-
http://download.oracle.com/docs/cd/B19306_01/server.102/b14223/sqlmodel.htm#sthref1943
Which one I should adopt considering efficiency ? Is there any other way such as Pro*C could be used for the same purpose?
Please help with the best architectural decision to go about it, thanks
Warmest regards,
Ravion

Answer 1

Not sure what you are really asking?
NPV is a function provided within OLAP DML. You can use it directly within a custom measure or embed it within an OLAP DML program that can also be called directly from an custom measure. AWM with the Excel calculation builder utility (on the OLAP OTN Home Page) will allow you to quickly and easily add a custom measure to your AW.
I would look at the worked examples in the OLAP DML Help Guide. This will explain how to use the NPV function. Obviously you will need to create a new cube that contains all your main dimensions except time since the result returned by the NPV function is dimensioned by all the dimensions of your cashflow model except its time dimension. If your cashflows model is dimensioned only by the time dimension then NPV will return just a single value.
The following example explains using DML statements how to use the NPV function by creating a dimension called project, add values to it, and create a variable called cflow, which is dimensioned by year and project.
DEFINE project DIMENSION TEXT
MAINTAIN project ADD 'a' 'b' 'c' 'd' 'e'
DEFINE cflow VARIABLE DECIMAL <project year>When you assign the following values to CFLOW,
------------------------CFLOW----------------------
             -----------------------PROJECT---------------------
YEAR             a          b          c          d          e
Yr95           -200.00    -200.00    -300.00    -100.00  -200.00
Yr96            100.00     150.00     200.00      25.00    25.00
Yr97            100.00     400.00     200.00     100.00   200.00Using AWM these values would need to be stored in a relational table and then mapped to your cashflow cube. To view the results of an NPV calculaltion you could use the following statement:
REPORT NPV(cflow, .08, year)uses a discount rate of 8 percent to create the following report of the net present value of the cflow data.
NPV(CFLOW,
PROJECT        .08, YEAR)
a                  -21.67
b                  281.82
c                   56.65
d                    8.88
e                   -5.38within AWM this would be used to drive a custom formula where the formula itself would simply be the statement NPV(cflow, .08, year). You could even parameterise the middle value from a dimension to provide a series of NPV scenarios.
Hope this helps
Keith Laker
Oracle EMEA Consulting
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