Master data and Transaction data question

Hi all,

I am a newbie to sap bi and have the following question about master data and transaction data.

In a hypothetical scenario where:

master data table contains the following fields: cust_id, cust_name, cust_phone.

transaction data table contains the following fields: cust_id, cust_purchaseamount

I understand that master data is loaded less frequently and the transaction data is loaded frequently.

I am trying to load Master data first and for that I am creating separate info objects for cust_id, cust_name, cust_phone. I also understand the process to load master data into the BI system by creating a datasource and all that.

My question here is, while loading the transaction data, do I create a separate infoobject for cust_id or do I use the one that I created for loading the master data.?

If I have to use the same one as one created for master data, will its datasource not be mapped to master data?

If I have to create a new infoobject for cust_id, how will the link be established between this and the infoobject created for master data?

I sincerely appreciate any help in this matter.....