Abstract. A data warehouse is a subject oriented, integrated, non-volatile, and time variant collection of data in support of management's decisions. Dimensional modeling is a design technique used extensively in the design and construction of data warehouses. To account for different requirements there are several standard variations designers may utilize in their dimensional designs such as outriggers, bridge tables, mini-dimensions, slowly changing dimension techniques, etc. Our focus in this paper is on the representation of the dimensional schema as an ORM schema where slowly changing dimension techniques Types 1 and 2 are used. We examine the nature of the ORM schema - its objects, roles, constraints, rules and transactions.