Cloud Kicks (CK) wants to track orders against inventory, ensuring its ability to fulfill order...

Users need Read access to both master objects.

Request Inventory is a junction object with two master-detail relationships: Inventory and Order. For junction objects, access is based on the associated master records and the sharing behavior of the master-detail relationships. Salesforce documentation for object relationship considerations explains that sharing access to a junction object record is determined by access to both associated master records.

Why not the others? Sharing rules are not created directly on a master-detail detail object in the same way, because it is controlled by parent. Apex-based sharing is not needed. Read access to only the first master object is not enough because the junction record connects two master records.

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