An Introduction To Using Visual Analyst to Create an ERD

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An Introduction To Using Visual Analyst to
Create an ERD
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• Visible Analyst is a Computer Aided Software
  Engineering (CASE) Tool

• A quick Note In January 2003, The Visible
  Developer Professional Edition was selling for
  1,995 (Cheap!)

• Among the models included are

• Functional Decomposition (Business Model)

• Shows the business functions and processes they
  support in a hierarchical structure

• Entity Relationship Diagram (Data Model)

• Shows the data entities of an application and the
  relationship between the entities

• Object Model (Object Class Model)

• Shows classes of Objects, Subclasses,
  Aggregations, and Inheritance

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• Visible Analyst Models (Continued)

• State Transition Model (Real Time Model)

• Shows object transition to and from various
  states and conditions and the events or triggers
  cause them to change between different states

• Process Model (Data Flow Diagrams)

• Shows how things occur in the organization via a
  sequence of processes, actions, stores, inputs
  and outputs.

• Processes are decomposed into more detail,
  producing a layered hierarchical structure

• Product Model (Structure Chart)

• Shows a hierarchical, top-down design map of how
  the application will be programmed, built,
  integrated, and tested

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• Visible Analyst Models (Continued)

• Use-Case Model

• Shows the relationship between a user and the
  information system

• Activity Model

• A special form of the state diagram representing
  the performance of actions or subactivities

• Sequence Model

• Shows how objects collaborate in some behavior

• Collaboration Model

• Shows an interaction organized around the objects
  in the interaction and their links to each other

• Repository Model (Database Project_

• The Bible of Systems Analysis and Design

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• Open the Visible Analyst Program

• The First Thing You will see is the start-up menu

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• The Next thing you will see is the main menu

To start a new project, select New Project from
the File Menu
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• When you do, another pop-up menu will appear

Click the OK Button
You have now created a Project called Medical
which will be stored (in this case) at C\VISABLE
Analyst\Data
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• Once you have created a project, Visible Analyst,
  by default, assumes you will creating a new
  diagram

It just happens to be an ERD
(Which is what we want)
Click the OK Button
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• You will now see the ERD Drawing Screen

Lets First add the Entity PHYSICIAN
Click on the Entity Button
When you do, your cursor will change
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• Move the cursor to some position on the screen
  (Or keep it where it is)

• Then Right Click

• Another Pop-up menu will then appear asking you
  to name the entity (Object)

PHYSICIAN

• Label it PHYSICIAN

• Then Press OK

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• You Have now created the Entity Physician

• Next, we need to change to the select mode

• Next we right-click on our entity PHYSICIAN

(A Pop-up Menu Will appear)

• Choose Define

(We are going to add attributes)
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• Before we can go any further, we need to save our
  diagram

MEDICAL DATABASE

• Lets label our diagram as MEDICAL DATABASE

• And then Press OK

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• A New Pop-up Menu Will appear

• This menu will first ask us for a description of
  the entity

Contains Information about the Physician employed
by the hospital

• Describe what the database is for

(This will become part of the Repository)

• Put in an appropriate description

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• Alias ??

(We will talk about that later --- Maybe ---)
Contains Information about the Physician employed
by the hospital

• To add an attribute, Simply move your cursor to
  the add field, and start typing in the field name

PHYSID
Char
No

• As soon as you do, some default values come up

• These values refer to the data type,

the length,
and whether or not a Null value can be entered
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• We will first have to change the null (or
  missing) values, as necessary

Contains Information about the Physician employed
by the hospital

• In our case, we know that PHYSID should be of
  length 9

• Notes ??

• A GREAT idea Put in thoughts about what this
  means if it turns out to be wrong, you can
  change it later

PHYSID
Char
No
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This will be the primary key for the PHYSICIAN
table. It will also be the foreign key in table
PATIENT

• Now ADD the attribute to the entity

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• And the attribute has been added

• For the time being, lets assume that this is the
  only attribute

• Click on the EXIT button

A Dialogue Box will remind to save our entry

• Click YES

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• It may not look like we did anything, but we did

• There are three ways of viewing the screen

• The ENTITY LEVEL (which we are in)

• The PRIMARY KEY LEVEL

• The ATTRIBUTE LEVEL

• To see the attribute added, Click on the
  ATTRIBUTE Level View

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• Notice that the Entity (PHYSICIAN) and the one
  attribute we entered (PhysID) are displayed

• While we are at it, lets look at the PRIMARY KEY
  LEVEL screen

• Click on the PRIMARY KEY LEVEL Button

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Where is all the information?

• The PRIMARY KEY LEVEL Screen Shows ONLY the
  Entity Name and the Primary Key

• We didnt designate a Primary Key

• Lets make PhysID the primary key

• Once again, RIGHT-CLICK on the entity

• And again, Choose DEFINE

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• Adding a Primary Key is extremely simple

• Click on the primary key button

• A new dialogue Box will appear

• Click on the attribute you wish to make a Primary
  Key

PhysID

• And it will appear in the Columns in Key Box

• Now just press the OK Button

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• Notice that PhysID is now the Primary Key

• Now lets go back and see our Diagram Screen

• Click on the EXIT button

(This time there will be no reminder to save the
object)
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• Remember, we are still in the PRIMARY KEY LEVEL
  screen

• Lets Add another Attribute

(You know the drill)

• RIGHT-CLICK on the entity

• And again, Choose DEFINE

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• Lets Add the attribute PhysName

• Once again, the default values will appear in the
  Type and Null Fields

What if we dont Want the data type Char or we
wished to allow Null Values?
PhysName
Char
No

• Change them

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• Lets change the attribute PhysName to an
  integer

(Yes -- I know thats dumb, but bear with me)

• Click on the Scroll Bar button

PhysName
Char
No
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• The list of all available data types will appear

• Choose the one you want

• Integer ???

• Small Integer ???

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• Clicking on the Null Scroll Bar will cause the
  possibilities to be displayed

• At any rate, we want the attribute PhysName to
  be of data type Char and of length 30

(Which we would signify by entering 30 in the
length field)
30
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• Once again, after we have added our attribute, we
  need to add it to the list

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• As soon as we hit the add button, it will be
  added to the list

• Lets go back to the Diagram Screen

• Click Exit

(Again, there will be no reminder to save)
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(I have added a few more Attributes)

• Notice that we are in ATTRIBUTE LEVEL Mode

What if we want to add a constraint to an
attribute ??

• Not a problem all we need to do is go back to the
  Define menu

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• Click on the Check Constraints Tab

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• Click on the Column Check Constraints Scroll Bar

(The complete list of attributes will appear)

• Highlight the attribute you wish to put
  conditions on and click

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• Click the Add/Remove Button

• Add the condition

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• Now lets add the entity PATIENT

• Click on the Entity Button

• Put the entity wherever you want

• Once again, the label entity dialogue box will
  ask you to label the object

PATIENT

• After that, Click on the OK Button

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• Add PATIENT Attributes as we did before

(Make sure you first choose the Select Mode)

• Notice also that I have expanded the ENTITY folder

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• Were now ready to link the tables together

• Choose the appropriate relationship from the menu
  bar

(In our case, this is a one (mandatory) to many
(optional) relationship)
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• After you click on the relationship button,
  simply connect the tables with your cursor

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• Another Dialogue box will appear asking you
  questions about the relationship

Treats
Treated By

• May a Physician have Zero patients?

• Enter the name of the relationship from PHYSICIAN
  to PATIENT

• Enter the name of the relationship from PATIENT
  to PHYSICIAN

• Click the OK Button

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• And we have set up a relationship between the
  tables

Have We ??

• One nice feature about Visible Analyst is that it
  will Analyze our diagram for us

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• Click on the DIAGRAM Tool bar option

• Now click on the Analyze Option

• Another Menu will pop-up with available options

• Click the OK Button

• And, we Appear to be OK

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• Keep in mind that Visible Analyst is MORE that
  just a diagramming tool

• It also maintains our REPOSITORY

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• Before going on, lets review what a Repository
  does

• A repository is a database for a project that
  contains information both captured from your
  diagrams and entered directly by you.

• It contains metadata that describes the
  organizations data and data processing resources

• Provides information about

• What users must know what

• What automated CASE tools that are used to
  specify and develop information systems

• All Applications that access and manipulate data

• The DBMS that maintain the repository and update
  system privileges, passwords, and other
  information

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• Now, getting back to our Example

• To check our repository, click on the
  REPOSITORY Tool bar option

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• Lets do a Key Analysis

• We forgot to add our foreign key

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• The procedure for adding a foreign key is
  straight-forward

• RIGHT-CLICK on the entity

• And again, Choose DEFINE

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• One of the options on the Define Item Menu is
  Foreign Keys

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• First, Click on the attribute you wish as a
  foreign key

Physician

• Then click on the field you want to relate the
  foreign key with

(The attribute will be added)

• Save it

• And Exit

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• Notice that our ATTRIBUTE LEVEL Screen reflects
  the addition of the foreign key

• Lets check our repository to make sure
  everything is OK

What is going on ??

• Pick Key Analysis

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• There are actually a few problems

• Remember how we defined our PHYSICIAN Table

• And our PATIENT Table

• We have a mismatch between PHYSICIAN.PhysID and
  PATIENT.Physician

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• Another benefit of Visible Analyst is that it
  will correct these types of problems automatically

• Once again, Click on Repository

• Now Click on Key Synchronization

• The Pop-up Menu will give you some options

• Click OK

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• You will be asked to save your synchronization

• So, Save it

• Save this file too

NameItWhatYouWish
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Are we OK now ??

• Lets Check ---

• Click on Key Analysis

• We appear to be OK

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• Lets once again take a look at our tables

• First, our PHYSICIAN Table

• Next, our PATIENT Table

• The Issue has been resolved

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• I have added two more entities

(You know how to do this)

• Lets add the Associative entity TREATMENT

• Aside from clicking on the Associative Entity
  Button (instead of the Entity Button, the
  procedure is the same

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• Next use the mouse to connect the entities

• Then fill in the necessary information

• First, lets relate PATIENT and TREATMENT

(This is a (mandatory) 1 to (optional) Many
relationship)
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Are we OK now ??

• Lets Check

• Note that this is a WARNING not an ERROR

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But what about the Repository ??

• Lets Check that

• Once again, we forgot our Foreign Keys

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• Open the DEFINE Menu

(Right-Click on TREATMENT)

• Go to the Foreign Keys Option

• First link PATIENT and TREATMENT

• Choose the relationship

• Then add the attribute

• Move it to the Link

Patient

• This time, Click on Migrate

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Migrate ??

• Key Synchronization migrates primary keys
  across normalized relationships to make Foreign
  Keys in other Entities

• It also adds descriptive information about the
  relationship and the related entities to the
  Repository

• When you created the entity, the Repository
  created an Associator Element Name for it

• Visible Analyst uses this information for Key
  Analysis and Synchronization

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• Do the same thing for the other relationships

• Select the relationship between TREATMENT and
  PRESCRIPTION

• Add the attribute

• Move it to the Link

• Migrate

Prescription

• Do it again for the relationship between
  TREATMENT and ILLNESS

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• Notice that a strange thing has happened

• The attribute names have been changed to
  correspond with their labels in the tables they
  refer to

(Due to Synchronization)

• We could change them, or just leave them as is

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Are we OK now ??

• Lets Check

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• The Only thing we havent done is set-up our
  Unary Relationship

(But we know how to)

• Draw the relationship

• Right-Click on PHYSICIAN

• Choose Define

• Add the field Supervisor

• Set Supervisor as a Foreign Key

-- And Were Done ---
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How do we Open a Different Project ??

• First, Go to the File Option

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• Now Select the project

• Lets Choose Project TEST

• Then Click OK

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• Choose (highlight) Entity

• Now open up the Diagram

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• Lets Open the Drivers License ERD

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• Lets Review the ERD

The Department of Motor Vehicles (DMV)
Many Individuals Apply for Licenses
Has Many Evaluators
An Applicant May take may Road Tests
The DMV May (Must?) Issue Many Drivers Licenses
Each Evaluator Gives many Road Tests
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• Lets Look at some of Visible Analysts other
  (ERD) options

• We can Establish Database Security

• We can Modify The Balancing Rules

• We can Modify The SQL Dialect

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• We can Even

• Generate the DDS

(Data Descriptor Specification)

• Generate the SQL Code Needed

• Create Reports

• Create Report Queries

-- BUT NOT WITH THE STUDENT VERSION ---
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?? Any Questions ???
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