How will moving a database instance to a different compartment impact user access?

When a resource, such as a database instance, is moved from one compartment to another in Oracle Cloud Infrastructure (OCI), it becomes subject to the Identity and Access Management (IAM) policies of the new compartment. The policies that governed the resource in its original compartment no longer apply. Consequently, any user access that was granted through policies attached to the original compartment is effectively revoked. Access must be re-established through policies attached to the new compartment or a parent compartment in its hierarchy.

A. IAM policies are not tied to compartments. This is incorrect. IAM policies are fundamentally tied to compartments; they define permissions for resources within a specific compartment or the entire tenancy (root compartment).
C. Compartments prevent resource movement. This is incorrect. OCI is designed to allow the movement of most resources between compartments, providing organizational flexibility.
D. Compartments are not covered by IAM policies. This is incorrect. Compartments are the primary mechanism for organizing resources and are the scope to which most IAM policies are applied.

1. Oracle Cloud Infrastructure Documentation, Managing Compartments, "Moving a Resource from One Compartment to Another":

"When you move a resource to a new compartment, the policies that govern the new compartment apply immediately and affect access to the resource. Be aware of the following consequences: ... Access is controlled by the policies written for the new compartment. If you move a resource to a compartment where the current users don't have access, then those users will no longer be able to access the resource."

Source: Oracle Cloud Infrastructure Documentation, Doc ID: E97345-19, Section: "Managing Compartments".

2. Oracle Cloud Infrastructure Documentation, Overview of Identity and Access Management, "How Policies Work":

"Policies are comprised of one or more statements that specify which groups can access what resources and at what level of access. The policies are attached to a compartment or the tenancy. The attachment point determines who can modify or delete the policy."

Source: Oracle Cloud Infrastructure Documentation, Doc ID: E97345-19, Section: "Overview of Identity and Access Management".