Call Center calls fact table

Hi,

I need help implemmenting a fact table for call center calls.

My problem is the following: We receive a daily file from an external call center provider, with leads call interactions. The interactions goal is to sell the Insurance Policy, but during the process I can have 10 calls, and only the last one is in fact a confirmed sale (there is a lead number, common to all interactions). In the 10th line, I have enough information to get the policy number, and select the correct surrogate key.

How can I associate the policy number to all the other 9 attempts in a simple way? My table contains 30M records at the moment and I have 3M lead numbers.

At this moment I see two ways to do it, but don't know if they are good solutions:
- Update the existing records, whenever I receive a policy number
- Create an aggregated view, where I select the max value for the surrogate key (my unknown key is -1)

Kind Regards,

Pedro

Create a two column cross reference table with just the lead number and policy number. From there, use that table as a lookup during the fact loading process. Your cross reference table will only have 3M rows and two columns. That should work really well.