This BDD shows the composition hierarchy of an Order Processing System. Order Processing Web Services (at least the implementation) and Order Processing EJB are owned by the Order Processing System and do not exist outside of the system. Database is a shared RDBMS that contains tables for the Order Processing System, but other types of tables are in Database. Order Processing System interacts with another system "Invoice Message System".
|BDD Featuring Part and Reference Properties|
Database is connected to system using an aggregation or shared association connector. This connection classifies the block "Database" as a reference property. System then displays a references compartment.
Finally, a very loose association is established between Order Processing System and Invoice Message System. Order Processing System doesn't know anything about Invoice Message System, but might simply publish a message on a queue that both systems know about. EA does not add this item as a property automatically, although one can be created manually.
EA's Project Explorer shows the composition hierarchy by displaying parts of System as children.
|Order Processing System Composition Hierarchy in EA Project Explorer|
EA also has a dialog that can be displayed using a right-click on a block that shows block's Structural Elements. The following dialog shows the part and reference properties of System.
|Structural Elements Dialog|