In Force.com, individual data records within an object are secured through a combination of three concepts:
1. Record ownership—All records except those on the child side of a Master-Detail relationship have a single named owner. Record owners are individual users or groups of users. Ownership of a record can be transferred manually to another user or group.
2. User groups—Users can be organized into flat lists and placed in a hierarchy. Groups can contain individual users as well as other groups.
3. Sharing model—The sharing model consists of two parts: organization-wide defaults and sharing reasons. The organization-wide defaults can be configured to lock down all records by object, regardless of their owner. Sharing ...