Component diagram
Component diagrams show relationships between components and their properties.
The image above shows the simplest form of a Component diagram. It shows three (software) components and their dependencies. From it, we can determine that the components for client and item management can work independently of other components, while the order management component has dependencies on the other two components. This diagram provides no information about the nature of these dependencies.
The component dependencies can be described in more detail by using ports and interfaces. The following shows an example of this.
The client management component uses a port to provide an interface called customer data access, which can be used to retrieve customer data from the component. Likewise, the item management component also provides a corresponding interface called item data access. In turn, the order management component uses two ports to specify that it requires access to the customer data access and item data access interfaces. Two dependency relationships illustrate the access to the interfaces.