1. CSIS 254 Oracle Database Design
CSIS Introduction to Oracle
CSIS 254 Oracle Database Design
Day 3
Day 1

2. CSIS 252 - Introduction to Oracle
Today’s Agenda
Questions on homework
Review key concepts from last week
Continue with Analysis stage of SDLC
Entity Life History Diagrams
Data Flow Diagrams
Relational Databases
Day 1

3. Seven System Development Stages (Review)
CSIS Introduction to Oracle
Seven System Development Stages (Review)
The Software Development Life Cycle
Strategy / Scope
Analysis
Design
Programming
Testing
Go Live
Production & Maintenance
Day 1

4. The Entity Relationship Model (ERM) Entities
CSIS Introduction to Oracle
The Entity Relationship Model (ERM) Entities
Entities are people, places, things, or events of interest to our system that can be divided into distinct classes
An entity may describe physical things, or it may be conceptual
Entity types (or sets) are collections of entities having similar properties
Each occurrence of an entity type can also be called an instance or an object
Day 1

5. The Entity Relationship Model (ERM) Attributes
CSIS Introduction to Oracle
The Entity Relationship Model (ERM) Attributes
Attributes are relevant properties or characteristics that describe the entity instances in an entity set
An attribute may be simple (atomic) or composite
An attribute may also be single-valued or multi-valued
The values of an attribute in an entity instance may be restricted:
mandatory, uniqueness, formatting, restricted domain...
Day 1

6. The Entity Relationship Model (ERM) Keys
CSIS Introduction to Oracle
The Entity Relationship Model (ERM) Keys
An attribute (or combination of attributes) that uniquely identify an entity is called a key attribute
Key attributes are limited to the minimum set of attributes that can uniquely identify an entity
When an entity has more than one set of key attributes, they are called candidate keys
When a key does not contain any descriptive data about the entity,it is called a surrogate or natural key, or an identifier
Day 1

7. The Entity Relationship Model (ERM) Derived Attributes
CSIS Introduction to Oracle
The Entity Relationship Model (ERM) Derived Attributes
A derived attribute is one that can be determined based upon the values of other attributes in the entity object or related entity objects
These might it be beneficial for us to include derived attributes in our physical database design
Performance
Redundancy
Security
Consistency (??)
Snapshots in time (as of)
Day 1

8. Engineering Method Entity Diagrams
CSIS Introduction to Oracle
Engineering Method Entity Diagrams
Entity Name
Attributes
PALOMAR STUDENT
Student ID
Full Name
First Name
Middle Name
Last Name
Social Security Number
Home Address
Home Phone
High Schools
Day 1

9. Engineering Method Entity Diagrams
CSIS Introduction to Oracle
Engineering Method Entity Diagrams
PUBLISHER
Publisher Id
Publisher Name
Street Address
City
State
A familiar Key
example Attribute
Day 1

10. The Entity Relationship Model (ERM) Weak Entity Types
CSIS Introduction to Oracle
The Entity Relationship Model (ERM) Weak Entity Types
Entity types that do not have key attributes of their own are called weak entity types
Weak entities are always related to specific entities from another entity type -- the owner
A weak entity must have a partial key or an identifier, which is a set of attributes that can be used to uniquely identify each instance from other instances belonging to the same owner
Day 1

11. The Entity Relationship Model (ERM) Subtypes and Supertypes
CSIS Introduction to Oracle
The Entity Relationship Model (ERM) Subtypes and Supertypes
When different entity types share the same attributes, we can break out the common attributes into Supertypes, leaving the attributes that distinguish entities into Subtypes
There must be at least one attribute that distinguishes subtypes common to a supertype
An entity instance must belong to one and only one subtype
Day 1

12. The Entity Relationship Model (ERM) Relationships
CSIS Introduction to Oracle
The Entity Relationship Model (ERM) Relationships
A relationship is an association between two or more entities
Each relationship has an inverse relationship
Participation or optionality refers to whether each entity instance must occur in the relationship (i.e., is it a mandatory relationship)
The degree of a relationship is the number of participating entity types
Day 1

13. CSIS 252 - Introduction to Oracle
Cardinality
Cardinality is the maximum number of occurrences of each entity type that can occur in a relationship
In binary relationships:
A 1-to-1 relationship occurs when an entity of one type can occur in (at most) one relationship with an entity of the other type
A 1-to-many relationship occurs when an entity of one type can occur in (at most) one relationship with the other type, but entities or the second type can be related to any number of entities of the first type.
A many-to-many relationship occurs when no restrictions exist on the number of entities that can participate in a relationship
Day 1

14. Relationships ER Diagrams
CSIS Introduction to Oracle
Relationships ER Diagrams
In ERDs, entities that are related are connected by lines. (A 1-to-1 relationship is shown below.)
SOCIAL
SECURITY
NUMBER
PALOMAR
STUDENT ID
Day 1

15. Relationships ER Diagrams
CSIS Introduction to Oracle
Relationships ER Diagrams
Crow’s feet are used at the “many” end in 1-to-many relationships.
has had as
Head of State
COUNTRY
RULER
Day 1

16. Relationships ER Diagrams
CSIS Introduction to Oracle
Relationships ER Diagrams
Both sides of the line will have crow’s feet in a many-to-many relationship.
CAR
MODEL
is available
using
COLOR
GROUP
Day 1

17. Relationships ER Diagrams
CSIS Introduction to Oracle
Relationships ER Diagrams
A small circle is placed at the end of an optional participation, and a small perpendicular line placed at the end of a mandatory participation.
is biological
mother of
WOMAN
CHILDREN
Day 1

18. Relationships ER Diagrams
CSIS Introduction to Oracle
Relationships ER Diagrams
Subtype entities reference their supertypes using arrows, rather than lines.
LICENSED
VEHICLE
CAR
TRUCK
BIKE
Day 1

19. Relationships ER Diagrams
CSIS Introduction to Oracle
Relationships ER Diagrams
All entity occurrences must fall into one of the subtypes
We add an “other” category to include RV’s, planes, motorcycles, etc.
LICENSED
VEHICLE
OTHER
CAR
TRUCK
BIKE
Day 1

20. CSIS 252 - Introduction to Oracle
ER Diagrams
Relationships are (optionally) shown in diamonds connected to the associated entities
meet in
Super Bowl
NATIONAL
LEAGUE
CHAMP
AMERICAN
LEAGUE
CHAMP
Day 1

21. Reflexive (Recursive) Relationships
CSIS Introduction to Oracle
Reflexive (Recursive) Relationships
Occur when an entity has a relationship with another entity in the same entity set
We might need to add business rules prohibiting certain recursive conditions
If participation is mandatory, then the relationship is circular
If the relationship is hierarchical, then participation is optional
Day 1

22. CSIS 252 - Introduction to Oracle
ER Diagrams
Reflexive relationships are drawn with a single entity box
is married to
PERSON
Day 1

23. Entity Life History Diagrams
CSIS Introduction to Oracle
Entity Life History Diagrams
Entity-Relationship Diagrams describe the data in our system, but have no sense of order or sequence
Functional hierarchies or specifications describe processes
Entity Life History Diagrams (ELH) pull the two together for each entity
They are also commonly known as State Transition Diagrams, as entities pass from creation to their final states (archived, deleted, distributed, etc.)
Day 1

24. Generic Entity Life History Diagram
CSIS Introduction to Oracle
Generic Entity Life History Diagram
Entity
Creation
Transactions
Deletion or
Archive
Event 1
Event 2
Event 3 *
Event A
Event B o o
Day 1

25. Entity Life History Notes
CSIS Introduction to Oracle
Entity Life History Notes
The single entity being examined appears at the top of the diagram
The rest of the diagram is comprised of events, which create, modify, or delete instances of the entity
A little ‘o’ in the upper-right corner of an event means “option” or selection
An asterisk ‘*’ in the upper-right corner means “iteration” or repetition
Basic flow of diagram is left-to-right
Day 1

26. Entity Life History Example
CSIS Introduction to Oracle
Entity Life History Example
Payroll Check
2 years
pass
Job Cards
Transferred
Processing
Archive
Reviews
Made
Hours
Summarized
Calculations
Performed *
Check
Printed
Approved
Rejected o o
Day 1

27. CSIS 252 - Introduction to Oracle
Data Flow Diagrams
Are used to uncover as many data elements as possible in our data dictionary
Document the system from the data’s viewpoint (i.e., are data-centric)
Contain several entities on each diagram (unlike Entity Life History Diagrams)
Differentiate manual from automated processes
Show both external and internal processes
Day 1

28. Data Flow Diagram Example Purchase Requisition Fulfillment
CSIS Introduction to Oracle
Data Flow Diagram Example Purchase Requisition Fulfillment
EMPLOYEE
D1 Inventory
confirm
place req.
D2 Accts Payable
update
stock
issue req. P1
match to invoice
receive item P3
review &
approve
ship item
BUYER
issue P.O.
SUPPLIER P2
create order
send to
Day 1

29. Data Flow Diagram Notes
CSIS Introduction to Oracle
Data Flow Diagram Notes
Rectangles represent entities
Open-ended rectangles represent databases or data stores, and are labeled by a small box on their left
Rounded rectangles represent processes, with the top part of the rectangle having a process number
Arrows represent data flows (either electronic or physical)
Flow is generally from left-to-right
Entities may appear more than once in the diagram to preserve the flow and directional nature
Day 1

30. Data Flow Diagram Rules
CSIS Introduction to Oracle
Data Flow Diagram Rules
All processes must have at least one flow of data coming in and one going out
All processes on the diagram should modify the incoming data and create new forms of outgoing data
Each data store and each external entity must be involved with at least one data flow
Day 1

31. Relational Databases (Review)
CSIS Introduction to Oracle
Relational Databases (Review)
In relational databases, all data is stored in tables, which correspond roughly to entities
Each table is two-dimensional, consisting of rows and columns
Each row in a table, called a t-uple, corresponds to an occurrence of the entity
Columns in each table contain similar data across all rows in the table
Day 1

32. Relational Database Example
CSIS Introduction to Oracle
Relational Database Example
The following table is an example of a relational table describing classes that students have taken at a mythical college used in the rest of this lesson
Student Student Course
Id Name Id Course Name Grade Term Teacher
Joe Adams CSIS-840 VB Concepts C Spr-02 Wilkins
Joe Adams CSIS-824 Intro to C++ B Fal-02 Smythe
Joe Adams CSIS-740 Oracle Admin A Spr-03 Wallace
Jane Smith CSIS-941 Systems Des. B Fal-02 Evans
Jane Smith CSIS-840 VB Concepts B Spr-02 Wolkins
Ida Know CSIS-184 Networks A Sum-03 Farmer
Eunice Eye CSIS-824 PowerPoint W Spr-02 Simpson
Day 1

33. Relational Database Example
CSIS Introduction to Oracle
Relational Database Example
Each row (or t-uple) in the table describes a Class taken by a Student in a term at our college
The data in each column is consistent throughout the table
However, there are three inconsistencies in the table itself. Can you find them?
Day 1

34. CSIS 252 - Introduction to Oracle
Primary Keys (Review)
Each row in a table has a primary key, which is the column or set of columns identified to our DBMS that uniquely identifies it from every other row in the table
No attribute value in a primary key can be NULL
A table can have only one primary key
If a primary key is not specified, Oracle supplies one
What would be the primary key for our sample database?
Day 1

35. CSIS 252 - Introduction to Oracle
Foreign Keys (Review)
An attribute (or group of attributes) in a table can also be a foreign key, meaning that it references the primary key (or at least unique attribute) to another table
An example would be a Customer Id attribute on an invoice header, which would reference the customer account information for that invoice
Day 1