This paper addresses integrity rules that are embedded within engineering design applications and that apply between applications. A representation for integrity rules that are embedded in applications is presented and a set of related methods developed for: (a.) maintaining the integrity condition of application developed data, (b) managing the precedence order between applications, in the context of (c.) changing the schema and the associated mix of applications and (d.) iterated execution of applications and change propagation. Both integrity rules literally embedded within external applications and others required to be embedded within a database are considered. The techniques are demonstrated with an extensive example.