VIS201d Visio Database Diagramming

VIS201D Visio Database Digramming 1
An introduction to Visio database diagramming
for analysts and IT professionals
P.O. Box 6142
Laguna Niguel, CA 92607
949-489-1472
http://www.ocdatabases.com
Welcome to VIS201D – Visio
Database Diagramming
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Visio Database Diagramming
• Introduction (s)
• Facilities
• Course Packet (contents may vary)
– Student questionnaire
– Collaterals (Maps, Catalogs, Etc.)
– PowerPoint handouts
– Evaluation form
– Training certificate
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Bookstore2 VIS201D Visio Database Digramming 3
VIS201D Contact Information
P.O. Box 6142
949-489-1472
slides.1@ocdatabases.com
Copyright 2017. All rights reserved.

VIS201D Resources
• Bookstore database scripts found on
box.net at
http://tinyurl.com/SQLScripts
• Slides can be viewed on SlideShare…
http://www.slideshare.net/OCDatabases
• Follow up questions?
support@ocdatabases.com

• Entity Relationship Diagrams (ERD’s)
• Relational Databases
• Entities
• Attributes
• Relationships
– 1 to many
– Many to many
– 1 to 1
– Recursive
– IS-a (subtypes)
Bookstore2 VIS201D Visio Database
Digramming
5

• Course focus is using Visio to create an
ERD (Entity Relationship Diagram)
• Widely used for:
– Database development
– Database administration
• ERD’s are a foundation skill for work in
the Database field much like SQL
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• A basic knowledge of relational databases,
perhaps via MS Access, or some
programming knowledge, is desirable
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VIS201D Approach
• Create a complete ERD
– In this class using Visio; another class uses
Lucidchart on-line tool
• Step-by-step
• Use same bookstore database used in our
SQL classes
VIS201D Visio Database
Digramming
8Bookstore2

Relational Database Evolution
• Based on Codd’s paper
• Early commercial efforts focused on Unix
• First mainframe implementation by IBM -
precursor to today’s DB2
• First PC implementation in early 80’s by
Oracle
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Relational Database
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Database Design Models
(Entity Relationship Diagrams)
We will start here
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Logical ERD Development
• Create entities
– Add attributes (fields)
– Set attribute properties (PK, FK, required)
• Draw the relationships from the parent
tables to the child tables
VIS201D Visio Database Digramming 12Bookstore2

ERD Development
• We will use the bookstore database used in our
SQL classes for our examples
• At this time we will just create two tables
– Customers
– Orders
• Although a little odd we will stick with the field
names used by the author
• These two tables are in a one-to-many
relationship

ERD Drawing Tools
• Embarcadero
• ER-WIN
• Visio (used in this class)
• Oracle Designer
• Many others
(Note: most tools use the crows-foot or similar model.)
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Customer Entity
• CUSTOMERS
• Attributes (fields):
– Customer_numb
– Customer_first_name
– Customer_last_name
– Customer_street
– Customer_city
– Customer_state
– Customer_zip
– Customer_phone
– Customer_email

Start the Visio Drawing
• Start Visio and
select software
and databases
• Use the crow’s
foot notation
• Save your
drawing

Initialize the Customer Entity
• Drag an entity
shape to the
drawing surface
• Zoom in to give
yourself some
working room
• Note by default
it set the 1st
attribute as the
primary key

Attributes
Customer entity
Customer
_numb
Customer_first_name Customer_last_name
12 Al Le
13 Bobby Jones
14 Carol Gomez
15 Hank Tartanian
166 Mary Park
167 Nancy Bocage
attributes
values
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Add remaining attributes
• Drag an
attribute shape
to the drawing
surface, or
• Click insert
attribute

Keys
• Derived from entity identifier
• One or more attributes (more = composite key)
• Uniquely determine a row
• Functionally determine an entire row’s
attributes
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Set attribute properties
• Mark any
attribute
properties such
as required or
primary key
• In our example
we only have
one required
field. This may
or may not be
realistic for
your databases.

Add Orders Entity
• Conventions
used:
– Entity name in
caps
– Underline pk’s
– Italicize fk’s
– Bold required
fields
• Not necessary,
really, but can
be used to
create a sort of
text ERD
• ORDERS
– Order_numb
– Customer_numb
– Order_date
– Credit_card_numb
– Order_filled
– Credit_card_exp_date
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Orders Entity
• Follow steps
used for
customers entity
• Note
customer_numb
marked as FK
(foreign key)

Relationship Properties
Has /
Belongs toEmployee Dependents
1 N
Degree
Cardinality
Optionality
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Relationship Types (after David Kroenke)

Create initial relationship
• Pin one side to
customers
• Drag crows foot
to orders

Create relationship
• Adjust
relationship
properties
– End size
– End symbols
– Line thickness
• Add titles,
colors, etc.
• This completes
the logical ERD

Annotate relationship
• Annotate the
relationship if
desired
• Use two
phrases, one for
each direction

Physical Database Design
• Expand logical model with attribute
properties
• Translate model to the Database
– Entities -> tables
– Establish primary & foreign keys, indexes
– Many-to-many relations ->Junction tables
– Business rules -> triggers, constraints, etc.
• Typically done with a “CASE” tool
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Add attribute properties column
• Right click on
the table
• Select show
attributes to add
an attribute
properties
column

Data Types
• int – whole number
• char (n) – fixed number of characters
• varchar (n) – variable number of characters
• float (m, d) – floating point with m digits, d after the
decimal point
• decimal (p, s) - fixed point with precision p, scale s
• datetime – date and time
• bit (n) – binary value with n bits
See the documentation for your specific database for exact
details plus other supported data types
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Customers Physical Design
• Set properties
for all fields

Orders Physical Design
• Set properties
for all fields
• Note optional
text boxes IX
for indexed
field with
duplicates
allowed, and
UX for unique

Database Design
MakesMfgr
One-to-many
Mfgr #
1 N
Equipment
PK=EqptID, FK=Mfgr#
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Database Design
HasInvoice
One-to-many (w/ ID Dependency)
Inv #
1 N
Line Item
PK = inv#, item#
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Bookstore Database Physical
Design (1st
two tables)
• Final physical
design
• This would be
basis for
implementing
the tables

Add Books Entity
• Conventions
used:
– Entity name in
caps
– Bold required
fields
• Not necessary,
really, but can
be used to
create a sort of
text ERD
• BOOKS
– isbn
– title
– publisher_name
– Publication_year
– binding
– source_numb
– retail_price
– number_on_hand
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Books Physical Design
• Set properties
for all fields
• Note optional
text boxes IX
for indexed
field with
duplicates
allowed, and
UX for unique

Connect Books to Orders NXM
• Create relationship
between books and
orders
• Note this is a many
to many
relationship
• It may be OK on an
ERD but cannot be
implemented
directly in a
relational database

Database Design
Mfgr
Many-to-many
Mfgr_Eqpt
Equipment
M N
Mfg # Eqpt ID
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Add Orderlines Entity
• Conventions
used:
– Entity name in
caps
– Bold required
fields
• Not necessary,
really, but can
be used to
create a sort of
text ERD
• ORDERLINES
– order_numb
– isbn
– quantity
– cost_each
– cost_line
– shipped
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Orderlines Entity
• Set properties for
all fields
• Note order_numb
and isbn form a
single, composite
PK. Both columns
are in the PK.

Bookstore 4 Table ERD
• This is a very
typical design
pattern
• All relationships are
now 1 to many
• Note intersection
table between
orders and books

Database Design
HasEmployee
Auto #
One-to-one
1
Auto
Emp #
1
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One-to-one demonstration
• There are no one-to-one relationships in
the bookstore database
• Instructor will demonstrate example
• Requires an FK with a unique index on it
Digramming
45Bookstore2

Recursive Relationships
Customer referrals
Customer_numb Customer_last_nam
e
Referred_by
12 Le 15
13 Jones 12
14 Gomez 13
15 Tartanian 166
166 Wang <null>
167 Park 166
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Database Design
Referred byMember
Recursive
Member #
1
M
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Add referred_by to Customers
Entity
• Referred_by is the
customer that
referred this one
• The referred_by
field is a FK which
points back to the
PK in the same
customers table.

Final Bookstore 4 Table ERD
• This is a very
typical design
pattern
• All relationships are
now 1 to many
• Note intersection
table between
orders and books
• There is a recursive
relationship
between customers
and itself

Database Design
Member
IS-A relationship (Subscriptions)
Print Online
Member#
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IS-A Relationships
• There are no IS-A relationships in the
bookstore database
• PK’s in child and parent tables are the
same
• Instructor will demonstrate
Digramming
51Bookstore2

VIS201D
End of Course
P.O. Box 6142
949-489-1472
Please fill out and turn in your
end-of-course evaluations.

VIS201d Visio Database Diagramming

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