You use data objects to model how documents, data, and other objects are used and updated during the process flow. Data Objects are artifacts that can represent many different types of objects, both electronic and physical.
Modeling data objects is optional: they do not have any direct affect on the Sequence Flow or Message Flow of the process flow, but they do provide information about what the process flow does. You can associate a data object with a process in two ways:
•You can use a normal type of association to connect the data object to a process.
•You can also select the data object and the process simultaneously, and associate them by clicking Draw > Associate Data Object with Process.