The system architecture diagram enables you to graphically model the applications of a system, and the externals that they interface with and data stores that they use or provide information to.

The following information describes the symbols used on the diagram:

You use the Application symbol to represent an entire application and graphically show on this diagram how it is related to externals and data stores. Within the application definition, you can specify overall information about the application -- the process threads in the organization that it enables, the type of team effort being used to build it, etc. To specify more details on the implementation of the application, you can create child Data Flow diagrams or UML diagrams, depending on the nature of the application (for example, structured or object-oriented or component-based).

You can model the flow of data as it moves from one point in the system to another with the Data Flow line. The flow might be between externals and applications, or applications and data stores. Within the data flow you can model the data elements and data structures used. Data flows can split into two or more flows, or they can join to one from two or more flows.

You can model the direction of the flow of physical items and materials in the system with the Material Flow line. The flow might be between externals and applications, or applications and data stores.

A Data Store symbol is where data "rests" when it is neither flowing nor being operated on. A data store can be a database, hard disk or a file on a disk.

A Multi-Data Store symbol is used to denote that multiple instances of the data store exists. This convention is used to avoid drawing a copy of a schema for each equivalent data store when you build a data model.

An External symbol represents an object that sends information or data to the system, or takes information from the system, but is not itself part of the system.

A Multi-External symbol is used to denote that multiple instances of the external exists.