A building management system includes an entity database and an identity management service. The entity database stores a plurality of interconnected smart entities. The smart entities include object entities representing a plurality of people or physical devices and data entities representing data associated with the people or physical devices. The smart entities are interconnected by relational objects indicating relationships between the object entities and the data entities. Each of the object entities includes a plurality of stored identity attributes. The identity management service is configured to receive a first identity attribute from a first device within a building, receive a second identity attribute from a second device within the building, compare the first and second identity attributes to the stored identity attributes of an object entity of the plurality of interconnected smart entities, and allow access to at least one of a building space, a device of building equipment, or a computer system in response to the first and second identity attributes matching the stored identity attributes of the object entity.