1. A method for providing an interface for object relationships, comprising: (a) receiving a selection of at least a first object and a second object stored in an on-demand database service and a definition of at least one relationship between the first object and the second object; (b) providing based upon the at least one relationship between the first object and the second object, a diagram illustrating the at least one relationship; and (c) providing an indication of how a data set resulting from applying the at least one relationship to the first object and the second object is expected to be represented in a report associated with the diagram.