Describe the core CPQ data model and the relationships between its key objects.

The Salesforce CPQ data model extends standard CRM objects with a set of managed package objects (prefixed SBQQ__):

1. SBQQ__Quote__c: The CPQ quote, a child of Opportunity. Holds the price book, account, billing/shipping, quote validity, and quote-level discounts.
2. SBQQ__QuoteLine__c: Each product line on the quote. Stores quantity, list price, customer price, net price, discount, subscription fields, and parent bundle references.
3. SBQQ__Subscription__c: Created when a quote is contracted; tracks each subscription product's term, quantity, and pricing on the Contract.
4. SBQQ__Contract__c: An extension of the standard Contract object with CPQ-specific fields (subscription term, auto-renew flag, MDQ settings).
5. SBQQ__Order__c / OrderItem: CPQ generates standard Orders and Order Products from a contracted quote. The SBQQ package adds subscription references back to the order item. Understanding these relationships — Quote → QuoteLine → Subscription → Contract → Renewal Quote — is essential for tracing how a deal moves from configuration to revenue.