A system stores and uses object relationships in a multi-tenant cloud-based identity and access management (IAM) system by: defining a schema for storing related objects, where the schema includes reference attributes indicative of relationships between the related objects in a database, and the schema defines a relationship type and a persistence scope for each reference attribute; constructing an in-memory representation of the related objects and their relationships based on the schema, where the in-memory representation indicates the relationship type and the persistence scope for each reference attribute; and using the in-memory representation of the related objects to perform an IAM service for a client of the multi-tenant cloud-based IAM system.