Unlike attributes of the basic attribute types, a reference attribute, or simply reference, describes a relation between the business object to which the attribute belongs and some other business object or business object group. For example, to register a relation between an account and its holder the configurator may define Holder attribute for Account object as a reference to Person object.

A reference attribute can be single, as in the example above, or multiple. Multiple references are useful for linking an object with several other objects, for example an account and transactions applied to the account. It is usually beneficial to configure a matching attribute on the related object. In the first example it could be an Accounts attribute on Person object listing all accounts held by the person, which, incidentally, would be a multiple reference.