Note: This a revision of an earlier post

RDM is an application to database management of mathematical relation theory (MRT) consistent with simple set theory (SST) expressible in first order predicate logic (SST/FOPL) that is used to formalize symbolically conceptual models of reality as logical models for database representation.

In RDM a domain can "appear" in multiple relations: the domain represents an abstract property, attributes defined on it represent that property in contexts of specific entity groups that relations represent. For example, attribute SALARY in relation EMPLOYEES represents the property represented by domain MONEY in the context of entities of type Employee and attribute BUDGET in relation DEPARTMENTS represents it in the context of entities of type Department.