New status for changed records or Additive Delta

Question

Hi Guys,
I have a design question for ODS and Extractor.
The requirement is as follows...
There is a table in CRM with service point as primary key. The fields in the table for example are bill account and Meter ID. Key figure is a XYZ value. In CRM for that Bill account Meter ID combination the XYZ value will change every year. In CRM the same record is being updated with changed value of XYZ. But in BW when the delta is being sent I do not want it to update the existing record but add it as  a new record. This way the history can be tracked for previous years XYZ value.
What is required to make this happen?
When creating the extractor I think I should give the delta as new status or additive delta?
What should I indicate as delta specified field?
For the ODS ( I am on BI 7.0) should I create the normal ODS or should I create the write Optimized or something for this requirement ( I dont remember right now the 3 types of ODS we can create).
Your inputs will be greatly appreciated.
Thanks
Kumar.

Answer 1

Thanks Puneet!
Good Answer.
New and Changed records does help in getting the records as desired.
But the problem is while loading into BW I cannot create a new record. The primary key is only Service Point. So even if the key figures and dates associated with that record changes, BW will still update my existing record.
Is there a possibility of using the dates as a pointer that a new record should be created.
Let me explain it better. Following is the structure of table.
Service Point (primary key)
Product GUID (key in CRM)
Circuit ID
Installation date
Effective date
Termination date
CRC (some key figure)
Scenario is - This year Service Point A with CRC value as 50 with effective and termination date for example .. May1 2009 - Apr 31 2010.
Service Point   CRC   EffectiveDate   TerminationDate
A                     50      5/1/2009         4/31/2010
Next year the same service point will have different values and CRM system will update the record in CRM table.
Service Point   CRC   EffectiveDate   TerminationDate
A                     60      5/1/2010         4/31/2011
1) So I was wondering if there is a way or some code can be written to check if effective and termination dates are not same it should be added to ODS as a new record.
2) Another way is to make some sort of Time dependency. Like use Valid From and Valid To dates to track the changes to the record and display all the different values for every record when the CRC values were valid between what dates.
3) or some other way you can suggest