How do I view data from OLAP DML program or statement?

Question

Hi
I'm struggling to find any information on this topic anywhere on the net:
How to view data produced by an Oracle OLAP DML program or statement.
Background :
I am using the latest AWM to create and maintain dimensions, cubes and measures. However, I've noticed that AWM, Discoverer OLAP, BI Beans, Excel Plug-In et al only provide a fixed set of formula and expressions.
For example, I wanted to created a Standard Deviation (STDEV) on measure. After much searching I learnt that I could do this by creating a custom measure in AWM by importing a measure defined in an XML dcoument as it's not provided by AWM. The output in Discoverer OLAP on the surface seems to give the correct results, however when drilling from high level to lower level of time time dimension hierarchy Discoverer includes the parent value in the calculation and renders the values incorrect.
My alternative is to use OLAP DML, as it provides a richer range of formuale and calculations possibilities and I was hoping to use this functionality to do create the measures. I have the distinct impression, however, that OLAP Worksheet is the only interface out there to do this.
It seems very primitive and limited with regards to data output, almost like SQL*Plus in many ways.
The burning questions I have are :
1) Do I need to write DML programs to perform these custom measure calculations and add them to cubes or do I import the custom measures via AWM and XML?
2) If the answer to question 1 is DML programming, is there a way of viewing the OLAP data output through a GUI interface without embedding the statements in SQL.
3) Has anyone experienced or noticed the same problem with Discoverer OLAP, AWM Viewer that I mentioned above? i,e, statistical functions performed on whole dimension hierarchy rather than lower levels.
I'm hoping someone out there knows what I am trying to do or get at. Keith, any ideas or suggestions?
Thanks
Kind Regards
Greg

Answer 1

Hi Greg,
There are two ways to achieve what you want. Both require the use of custom calculations which cannot be created via the calculation wizard within AWM. To do this the easiest way is step outside of AWM and use the Excel Calculation utility that is on the OLAP OTN home page:
Creating OLAP Calculations using Excel
http://download.oracle.com/otn/java/olap/SpreadsheetCalcs_10203.zip
Readme
http://www.oracle.com/technology/products/bi/olap/OLAP_SpreadsheetCalcs.html
(Oracle OLAP DML Reference contains a list of all the OLAP functions that can be used to create a custom calculation. http://www.oracle.com/technology/products/bi/olap/OLAP_DML_10.2.zip)
The Excel tool lets you assign your own formula to a measure and then uploads that measure definition into your AW. It is possible to import a custom calculation template into AWM using the menu option on the Calculated Measure node of each cube, but it is safer to use the Excel Worksheet as this directly uses the public XML API and is always best to use a public API rather than hacking XML templates.
There are two types of custom calculation:
1) Formula: using a formula you can directly call any of the OLAP functions. For example to create a measure that returns the standard deviation for a measure then you would enter the following as the formula for your calculated measure:
stddev(sales_revenue, time)
The easiest way to test if the measure is working as expected is to use the data viewer within AWM.
2) Programs - if the function you need is not provided or you want to do special processing to return a result you can create an OLAP DML program which can return a result. To do this use OLAP Worksheet to define the program and add a datatype to the DEFINE statement, such as :
DEFINE PRG_SD_SALES PROGRAM DECIMAL
In the program return the value you have calculated within your program. Within the program you can do just about anything but be aware that your program is going to fire for every cell within your virtual cube so it must be efficient and fast to execute. For a measure then you would enter the following as the formula for your calculated measure:
prg_sd_sales(time, products, geographies, channels).
The actual program code would look something like this:
DEFINE PRG_SD_REVENUE PROGRAM DECIMAL
PROGRAM
argument T_TIME TIME
argument T_PRODUCT PRODUCTS
argument T_GEOGRAPHY GEOGRAPHIES
argument T_CHANNEL CHANNELS
variable D_RETURN decimal
TEMPSTAT TIME, PRODUCTS, GEOGRAPHIES, CHANNELS
do
limit PRODUCTS to T_PRODUCT
limit CHANNELS to T_CHANNEL
limit GEOGRAPHIES to T_GEOGRAPHY
limit TIME to T_TIME
limit TIME add descendants using TIME_PARENTREL
limit TIME keep TIME_LEVELREL 'CAL_MONTH'
D_RETURN = stddev(SALES_REVENUE)
doend
return D_RETURN
END
This code computes a standard deviation the all months within the specified time range, at year level for all 12 months, at quarter level for the three months within the quarter ans returns NA at the month level.
As the code executes within a implicit loop you can only change the status fo dimensions that for part of that implicit by using the TEMPSTAT command. To test the program at the command line use the OLAP Worksheet and the SHOW command to just return one cell of data, DO NOT SIMPLY USE THE RPR COMMAND because you will have to wait for the whole cube to be returned. If you want to use the RPR command make sure you limit your base dimensions first! You can use PRGTRACE to debug your program code it is not working as expected. Again, the easiest way to test if the measure is working as expected is to use the data viewer within AWM, although this will not return debug information so send all your debug output to a file to capture any errors and/or trace the execution flow.
Hope this helps
Keith Laker
Oracle EMEA Consulting
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