The Unified Modeling Language is a standard of
specifying, visualizing, documenting modeling language used for:
analysis and implementation
business and other process.
The Unified Modeling language was developed by Object Management Group in 1997. UML is a language for business
analyst, Software architects and it is also used by the developers for
describing, specifying, documenting, etc.
UML is process independent and could be applied in the context of
Types of UML diagram
UML diagram is divided into two types: Structural UML
diagram and behavioral UML diagram
In this section we will discuss all types of diagram:
Class diagram is used to represents the static view of an
application. Class diagram are backbone of nearly every object
oriented programming. This diagram is described as the static structure of a
system. It shows relationship between attributes, object, classes and
Class diagram are used for many purposes, including
detailed design modeling and both conceptual/ domain modeling. The class
diagrams are the only diagram in UML which can be mapped directly with object
oriented languages and so they are widely used at time of constructions.
Following is an example of class diagram:
Above is an example of college management system which is
A user is a base class which has three derived class:
student, faculty and admin. These three classes inherit the properties and
methods of base class or parent class.
Object diagram are sometimes also known as instance
diagram. As object diagram are derived from class diagram so object diagram are
dependent on class diagram. The object diagram has a similar concept as class
diagram. Object diagram also represents the static view of a system but this
static view is the snapshot of an application for a particular moment. Object
diagram are very useful in exploring “real world” examples of instances or
object and the relationships between them.
Following is an example of object diagram:
Package diagram are termed as subset of class diagram but
sometimes developers treat them as a separate technique. The most common use of
package diagram is to organize use case diagrams and class diagrams.
Package diagrams can be built either physical or logical
relationship. Package diagram allows you to organize model elements into
groups, which makes UML diagrams simpler and easy to understand. Packages
represents the file folder that can be used on any UML diagrams, they are most
common in use case diagrams and class diagrams as they have tendency to grow.
Following is an example of package diagram:
The nature and behavior are different of component
diagram. These diagrams are used to model the physical aspects (like
executable, files, documents, libraries, etc) of the system. The purpose of
component diagram is different from other diagrams in UML. It does not describe
the functionality of the system rather describes the components used to make
Component diagrams are the static view of a system. Static view represents the organization of
the components at a particular time. A single component diagram is not used to represents
the entire system but a collection of diagrams represents the whole system.
These diagrams are used at the time of implementation
phase of an application. This diagram is necessary because application cannot
be implemented efficiently. Following is an example of component diagram:
Composite diagram are used to show the internal structure
of a classifier. It also shows the classifier interaction with environments.
The term “structure” of a classifier means the composition of interconnected
elements, represents the run-time instance that collaborates over communication
links to achieve objectives. In other words, composite diagram show the
internal part of the program.
Composite structure diagram is a static structure that
shows the internal structure of a class and interaction points to other parts
of the application. This diagram includes the internal parts, ports through
which they interact with each other and outside world. This diagram is a set of
interconnected elements that combine at runtime to achieve objectives.
Deployment diagram is the static implementation view of
the system. Deployment diagram describes the physical resources of a system
like components, nodes and connection. This diagram is used to visualize the
topology of the physical component. These diagrams consist of nodes and their
relationship. In other words, deployment diagram shows the hardware of your
system, where software are deployed.
Deployments diagram and component diagram are closely
related. Component diagram describes the components of the system and
deployment shows how they are deployed in hardware.
Activity diagram is the dynamic view of the system. It is
used to show message flow from one activity to another. This flow can be
branched or concurrent, sequential. In other words, an activity diagram is a
flow chart which represents the flow from one activity to another activity or
describe as an operation of the system.
Activity diagram describes the operation of the system.
These diagrams are not only used for dynamic visualization but also used to
construct executable system using forward and reverse engineering techniques.
Sequence diagram are also known as event diagram. These
diagrams describe the communication between the classes by exchanging messages
over time. It is a good way to validate and visualize various runtime
These diagrams focus on the message communication between
the numbers of lifelines. Sequence diagram describes the communication on the
basis of sequence of messages that are exchanged. These diagrams are the most
important UML for dynamic modeling, which focuses on the identifying behavior
within your system.
Use case diagram describes the dynamic behavior of the
object. By dynamic behavior it means the behavior of the system at running or
operating. Use case diagrams, shows the
functionality of the system using use cases and actors. Actions, services and
functions are the set of use cases. The “actor” is entities or people having
defined roles within the system.
Symbols and notation used in Use case diagram
System: System boundary is drawn using rectangle
having use cases. Actor is places outside the rectangle or system.
case: use case is drawn in oval shape. Label the oval that
represents the system functions.
is the user of the system.
is a relationship between an actor and use case. A relationship can be include
and extends. An arrow is labeled with include or extends.
State chart diagrams are also known as state machine
diagram and state diagram. These diagrams describe the behavior of the system.
State diagram are used in reactive objects whose states are triggered by
Communication diagram shows the interaction between the
objects in sequence. These diagrams describe both static view and dynamic view
of the system. Communication diagram,
formerly known as collaboration diagrams.
Interaction overview diagram are the combination of
sequence diagram and activity diagram. These diagram model a sequence of
actions and deconstruct more complex interaction into manageable occurrence.
The notation used in activity diagram, same notation should be used in
A timing diagram is a type of interaction UML diagram
that focuses on processes during specific period of time. A timing diagram is an
instance of a sequence diagram, except time which is shown from left to right
instead of top down.