Unread Implementing heirarichal structure in data warehouse

Question

I want to create a data warehouse for credit card application. Each user can have a credit card and multiple supplementary credit cards. Each credit card has a main limit, which can be sub-divided into sub-limits to supplementary credit cards as requested by the user. Let us consider the following example:
User “A” has a credit card “CC” with Limit “L” and its limit is $100,000.
User “A” requested for a supplementary credit card “CC1” which is assigned limit
“L1” = $50,000. He requests for another supplementary credit card “CC2” which is assigned limit “L2” = $100,000.
Source tables contain data like this:
1. src_client_card_trans: contains transaction data of client/user credit card usage (client_id, credit_card_number, balance_acquired)
Client_id     Credit_card_number     Balance_acquired
A     CC1     $20,000
A     CC2     $50,000
A     CC     $70,000
2. src_card_limits: contains client’s credit cards linked to credit limits.
Credit_card_number     Limit_id
CC1     L1
CC2     L2
CC     L
3. src_limit_structure: contains the relationship of limits and sub-limits.
Limit_id     Sub_Limit_id
L     L1
L     L2
I have designed two dimensions and one fact table. Dimensions are:
1. LIMITS: contains the limit_id.
2. CLIENTS: contains credit card user’s information.
And fact table is LIMIT_BALANCES_FACT, which have some fact columns with the above dimensions.
How can I implement the above scenario of limit hierarchy in data warehouse? Need your suggestions.
Thanks in advance

Answer 1

Much depends on how you want to analyze the data and there are a few options:
1) Use credit limit as an attribute of the customer dimension. This would allow you to create query filters that can just show those customers with a $100,000 credit limit. This would return a list of credit cards (since the attribute would be assigned to each credit card) and then you can simply add or just keep the parents of that result set.
However, this assumes you do not want to measure data specifically relating to credit card limit. For example it would not be possible to view a total amount spent by all customers who had a credit-limit of $100,000.
In this case the attribute, credit limit, is simply used to filter a result set
2) Create a separate dimension called Credit Limit and create three levels:
All
Range
Credit Limit
The level Range would contain groupings of credit limits such as 100-500, 501-1200, 1201-1,000 etc etc.
This would allow you to analyse your data by customer and by credit limit over time. Allowing you to slice and dice quickly and easily.
3) A second customer hierarchy could be added to the customer dimension. This would allow you to drill-down through different credit limits to customers to individual credit cards. It would be advisable to follow the same approach as option 2 and create some groupings for the credit limits to make the drill down easier for your business users to navigate:
All
Range
Credit Limit
Customer
Credit Card
Hope this helps
Keith Laker
Oracle EMEA Consulting
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