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UML Diagram

Unified Modeling Language-standard language for specifying, visualizing, constructing and documenting the artifacts of software system.

Types Of UML

Structural Diagram - represent the static aspect of the system. These static aspects represent those parts of a diagram, which forms the main structure and are therefore stable. These static parts are represented by classes, interfaces, objects, components, and nodes. Types - Class diagram, Object diagram, Component diagram, Deployment diagram

Behavioral Diagram - Any system can have two aspects, static and dynamic. So, a model is considered as complete when both the aspects are fully covered. It basically captures the dynamic aspect of a system. Dynamic aspect can be further described as the changing/moving parts of a system. Types − Use case diagram, Sequence diagram, Collaboration diagram, State chart diagram, Activity diagram

Interaction Diagram - It captures the dynamic behavior of a system and describes the message flow in the system, describe the structural organization of the objects and describe the interaction among objects. Types - Sequence diagram, Collaboration diagram.

Use Case Diagram

A use case diagram is a graphical depiction of a user's possible interactions with a system. A use case diagram is used to represent the dynamic behavior of a system. It shows the relationship among actors and use cases within a system.

Use - Provide with an overview of the usage requirements, Requirement analysis and high level design.

Use Cases - describes a sequence of action that provide a measurable value to an actor. Horizontal Ellipse.

Actors - specifies a role played by a user or any other system that interacts with the subject. Stick Figures.

Relationships - association : b/w an actor and use case or two use cases. generalization : b/w two actors or two use cases.

System Boundary - indicates scope of your system - the functionality that you intend to implement. Rectangle.

Eg - Online Examination : Uc - Login, Set Paper, Upload, submit etc

Actor - Examiner, Student

a generalization relationship is a relationship that implements the concept of object orientation called inheritance. The generalization relationship occurs between two entities or objects, such that one entity is the parent, and the other one is the child. The child inherits the functionality of its parent and can access as well as update it.

Association is the semantic relationship between classes that shows how one instance is connected or merged with others in a system. The objects are combined either logically or physically. Since it connects the object of one class to the object of another class, it is categorized as a structural relationship.

Data Flow Diagram

How data is processed by a system in terms of inputs and outputs.

Notation - Yourdan and coad AND game and sarson

Process - transforms incoming data flow into outgoing data flow.

Datastores - repositories of data in system.

Dataflow - pipelines through which pack of information flows.

Data flow dia layers(nested) - several nested layers. main(context dia) a single process node on a high level dia can be explanded to show a more detailed...

Context Dia - tope level(0) DFD.P=0.generalizes the func. of entire sys. in relationship to external entities.

External Entity - obj outside the sys with which sys communicates. sources and destination of in and out.

DFD Levels - 1st level main process..each can be broken into further.

ER Diagram

Help organize data in your project into entities and define the relation between entities. data stpred and retrieved in a efficient way.

Entities - A definable thing such as a person, object, concept or event—that can have data stored about it. Rectangle. Eg. employee, payment, location etc

Instance - specific eg of entity. eg. arushi's payment etc

Relationship - How entities act upon each other or are associated with each other. diamond . eg. employees process payment etc

Attributes - A property or characteristic of an entity. oval or circle.

Primary key - A candidate key chosen by the database designer to uniquely identify the entity set.

Foreign key - Identifies the relationship between entities.

Cardinality - Defines the numerical attributes of the relationship between two entities or entity sets. one to one , one to many, many to many.

Activity Diagram

a flowchart to represent the flow from one activity to another activity. The activity can be described as an operation of the system. The control flow is drawn from one operation to another. This flow can be sequential, branched, or concurrent. Activity diagrams deal with all type of flow control by using different elements such as fork, join, etc

Initial State : It depicts the initial stage or beginning of the set of actions.

Final State : It is the stage where all the control flows and object flows end.

Activities :The categorization of behavior into one or more actions

Flow/edges : The edges depict the flow of execution.

fork : node consists of one inward edge and several outward edges. beginning of parallel activity.

Join : all flows going into the join must reach is before processing may cont. d of parallel activity.

Decision Box: one flow entering and several leaving.

Condition : defining a guard which must evaluate to true in order to traverse the node.

Merge : several flows and entering and one leaving

Partition : who/what performing the activity

Sub Activity indicator : the rake in the bottom corner of an activity.

flow final : process stops at this point

State Chart Diagram

Provide a way to model the various states in which an object can exist.

Start - black dot

Stop - bulls eye

Guard condition - controls when a transition can/cannot occur. square bracket.

actions - process that occur when a process is in certain state

Sequence Diagram

diagram deals with some sequences, which are the sequence of messages flowing from one object to another.

Interaction among the components of a system is very important from implementation and execution perspective. Sequence diagram is used to visualize the sequence of calls in a system to perform a specific functionality.

used for both ananlysis and design purposes

Collaboration Diagram

The collaboration diagram is used to show the relationship between the objects in a system.is used to portray the object's architecture in the system.

The purpose of collaboration diagram is similar to sequence diagram. However, the specific purpose of collaboration diagram is to visualize the organization of objects and their interaction.

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Abstraction - and model that includes the most imp essential or distinguish aspects o something while suppressing or ignoring less imp immaterial or diversionary details .It allows us to manage complexity by concentrating ont he essential characteristics of an entity that distinguish it from all other kind of entities.

Encapsulation - hides implementation from clients.clients operate withour knowing how the implementation fulfills the interface.

less ripple effect

Modularity - breaking up of something complex itno manageable peices .helps to understand complex sys.the logical and physical decomposition of things

Hierarchy - any ranking or odering of abstraction into a tree like structure