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All About Use Case Diagrams - What is a Use Case Diagram, Use Case Diagram Tutorial, and More

today we're talking about use case

diagrams we'll look at what they're used

for what the various symbols and

notations mean and go over the basics of

how to get started building them a use

case diagram is a graphical

representation of what a system must do

and uses simplified terms so as to be

easily understood by lay people such as

stakeholders a use case diagram is a

dynamic or behavior diagram in the

unified modeling language meaning they

emphasize what must happen in a system

being modeled as opposed to a structural

UML diagram which focuses on things that

are contained in a system use case

diagrams model the functionality of a

system using actors in use cases use

cases are a set of actions services and

functions that the system needs to

perform in this context the system is

something being developed or operated

such as a website the actors are people

or entities operating under defined

rules within the system use case

diagrams are valuable for visualizing

the functional requirements of a system

that will translate into design choices

and development priorities they also

help to identify any internal or

external factors that may influence the

system and should be taken into

consideration they provide a good high

level analysis from outside the system

use case diagrams specify how the system

interacts with actors without worrying

about the details of how that

functionality is implemented let's check

out some basic use case diagram

notations and symbols the system's

boundaries are represented with a

rectangle which will contain your use

cases actors will be placed outside the

system's boundaries use cases are

signified using ovals these ovals are

labeled with actions that represent the

functions within the system actors are

the users of a system

represented by this actor symbol an

actor specifies a role played by someone

or some other system that interacts with

the subject illustrate relationships

between an actor and a use case with a

simple line for relationships among use

cases

use arrows labeled either uses or

extends he uses relationship indicates

that one use case is needed by another

in order to perform a task for example

in this credit card processing diagram

the view order form use case is needed

for the calculate total use case an

extends relationship indicates

alternative options under a certain use

case such as this relationship between

place order and credit card rejected

it's easy to make a use case diagram

using an automated drawing tool like

smart draw you can start with one of the

included use case diagram examples and

make it your own or use the blank

template which has all the basic symbols

docked to the work area and the tools to

connect everything at your fingertips

here are some tips to consider as you

build when thinking of use cases think

of the end goal of a user they don't

want to login or signup that's not a use

case the use case is more like make a

purchase actors don't have names they're

not Bob they represent the role of

someone interacting with the system like

customer or shipping keep your labels

short and the size of your use case is

consistent for a professional look for a

more detailed implementation of a user's

goal use a sequence diagram another UML

diagram you can build quickly with Smart

draw those are the basics of UML use

case diagrams we hope you have a better

understanding of how they work and how

to start making your own thanks for

watching

you

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