Question

What are the diagrams defined in the UML Standard. Give a one or two sentence description of each one.

Answer 1

The current UML standards call for 13 different types of diagrams: class, activity, object, use case, sequence, package, state, component, communication, composite structure, interaction overview, timing, and deployment.

These diagrams are organized into two distinct groups: structural diagrams and behavioral or interaction diagrams.

Structural UML diagrams

• Class diagram
• Package diagram
• Object diagram
• Component diagram
• Composite structure diagram
• Deployment diagram

Behavioral UML diagrams

• Activity diagram
• Sequence diagram
• Use case diagram
• State diagram
• Communication diagram
• Interaction overview diagram
• Timing diagram

Class Diagram
Class diagrams are the backbone of almost every object-oriented method, including UML. A class diagram models the static structure of a system. It shows relationships between classes, objects, attributes, and operations.

Package Diagram
Package diagrams are a subset of class diagrams, but developers sometimes treat them as a separate technique. Package diagrams organize elements of a system into related groups to minimize dependencies between packages.

Object Diagram
Object diagrams describe the static structure of a system at a particular time. They can be used to test class diagrams for accuracy.

Composite Structure Diagram
Composite structure diagrams show the internal part of a class.

Use Case Diagram
Use case diagrams model the functionality of a system using actors and use cases.Use cases are a set of actions, services, and functions that the system needs to perform. In this context, a "system" is something being developed or operated, such as a web site. The "actors" are people or entities operating under defined roles within the system.

Activity Diagram
Activity diagrams illustrate the dynamic nature of a system by modeling the flow of control from activity to activity. An activity represents an operation on some class in the system that results in a change in the state of the system. Typically, activity diagrams are used to model workflow or business processes and internal operation.

Sequence Diagram
Sequence diagrams describe interactions among classes in terms of an exchange of messages over time. A sequence diagram is a good way to visualize and validate various runtime scenarios. These can help to predict how a system will behave and to discover responsibilities a class may need to have in the process of modeling a new system.

Interaction Overview Diagram
Interaction overview diagrams are a combination of activity and sequence diagrams. They model a sequence of actions and let you deconstruct more complex interactions into manageable occurrences.

Timing Diagram
A timing diagram is a type of behavioral or interaction UML diagram that focuses on processes that take place during a specific period of time. They're a special instance of a sequence diagram, except time is shown to increase from left to right instead of top down.

Communication Diagram
Communication diagrams model the interactions between objects in sequence. They describe both the static structure and the dynamic behavior of a system. In many ways, a communication diagram is a simplified version of a collaboration diagram introduced in UML 2.0.

State Diagram
State chart diagrams, now known as state machine diagrams and state diagrams describe the dynamic behavior of a system in response to external stimuli. State diagrams are especially useful in modeling reactive objects whose states are triggered by specific events.

Component Diagram
Component diagrams describe the organization of physical software components, including source code, run-time (binary) code, and executables.

Deployment Diagram
Deployment diagrams depict the physical resources in a system, including nodes, components, and connections.