The following illustrates how relationships are presented in ER/Studio DA using the IDEF1X notation:
IE is considered to be semantically stronger than IDEF1X, supporting more abstract approaches to data modeling. IE is more flexible in supporting subtypes, permitting roll up (generalization) and roll down (specialization) transformations. In addition, primary keys are less prominent in the IE notation; therefore, its practitioners are less likely to think about logical key choice prematurely.