Information Systems Development
37C00200
Lecture: Final notes
30th March 2017
Dr. Riitta Hekkala
The course should have given you
•  Introduction to the information system development
process
•  Understanding of the importance of effective
communication and integration with users and systems
•  Systems development and design techniques (Use
Case Diagram, Class diagram, ER-diagram, Relational
database model, and how to refine relations with a set of
rules called the normal forms)
•  Basic knowledge on management issues in globally
distributed teams + basic knowledge on outsourcing
Importance and Benefits of Use cases
•  They are in a tracking format and help to understand
functionality
•  They represent the goal of an interaction between an
actor and the system
•  They improve communication between vendors and
software users
•  They are important for product and software
development, and they improve security issues
Assignment 1
What does “object-orientedness” mean?
•  A modeling principle that describes everything in a system using
two elements: 1) Objects, 2) Interactions between these objects
•  Object-oriented system analysis =
–  Analysis on how to define the system behavior with meaningful objects
and their interactions
Ship
product
Digital
inventory
Warehouse
worker Y
Customer X
Change
address
Customer
DB
Objects
Interactions
Objects
Objects know and can do things
Vehicle
Is a
Car
Seat count
Tyre size
How much fuel left
Put air conditioning
on
6
Weight
Power source
Max speed
Data (know)
Calculate CO2
emissions
Function (do)
Is a
Is a
Bicycle
Ship
Crew size
Cargo contents
Tyre size
Handle bar type
Assignment 2
BankGateway
Customer
RecipeCatalogue
favoriteRecipes
recipes
addToFavorites()
1
addRecipe()
1
findRecipe()
makePayment()
Warehouse
deliverers
Recipe
*
1
ingredients
*
isAvailable()
order()
1
*
1
Delivery
*
Ingredient
Product
quantity
substance
quantity
substance
deliver()
is a
*
*
Substance
1
name
1
CourierDelivery
deliver()
ER model elements
Relationship
Entity
Attribute
Entity: person, object, event or concept about which data
is to be maintained
Entity type: collection of entities with common
characteristics; Entity instance: single entity
Relationship: Association between the instances of one or
more entity types. Relationships can be thought of as
verbs, linking two or more entities.
Attribute: named property or characteristic of an entity
8
Identifier Attributes
•  Candidate key
–  Attribute (or combination of attributes) that uniquely identifies
each instance of an entity type
SSN
EMPLOYEE
NAME
- Every entity (unless it is a weak entity) must have a minimal set
of uniquely identifying attributes, which is called the entity's primary
key. Weak entity cannot exist without entity with which it has a CName
relationship.
Instructor
CourseDesc
Year
Course
CNumber
Credits
Section
9
SectionNumber
Belong_To
Semester
Assignment 3
Assignment 4
N
1
WORKS_FOR
EMPLOYEE
1
1
1
MANAGES
CONTROLS
N
WORKS_ON
!
!
DEPENDENTS_OF
Assignment 4
Assignment 4: From Conceptual
Model to Relational Model and
Normalization
Phase 1
ü Create a relation that includes all the
simple attributes of entity
ü Include all the simple component
attributes of composite attributes
ü Choose one of the key attributes of entity
as primary key for R
ü If the chosen key of E is composite, the
set of simple attributes that form it will
together form the primary key of R
Information Systems
Development
14
Phase 1
EMPLOYEE
FNAME MINIT
LNAM
E
SSN BDATE ADDRESS
SEX SALA
RY
DEPARTMENT
DNAME
DNUMBER
PROJECT
PNAME PNUMBER PLOCATION
Information Systems
Development
15
Phase 2
ü For each weak entity type with owner
entity type – create a relation, and include
all simple attributes and simple
components of composite attributes of
weak entity as attributes of relation
ü In addition, include as foreign key
attributes of relation the primary key
attribute(s) of the relation(s) that
correspond to the owner entity type(s)
Information Systems
Development
16
After phase 2
EMPLOYEE
ESSN
DEPENDENT_NAME
SEX
BDATE RELATION
SHIP
Information Systems
Development
17
Phase 3
ü For each binary 1:1 relationship type
relation: identify the relations that
correspond to the entity types participating
in relation (Manages: managers ssn +
manager start date – MGRSSN +
MGRSTARTDATE)
ü Include the simple attributes of the 1:1
relationship
Information Systems
Development
18
Phase 3 (binary 1:1 relationship)
DEPARTMENT
DNAME DNUMBER MGR
SSN
MGR
STARTDATE
Information Systems
Development
19
Phase 4
ü For each regular binary 1:N relationship
type identify the relation that represent
the participating entity type at the N-side
of the relationship type
ü Include as foreign key in the primary
key of the relations that represent the
other entity type participating in
relationship
Information Systems
Development
20
Phase 4: regular binary 1:N relationship
EMPLOYEE
F
NAME
MINIT
LNA
ME
SS
N
B
DATE
ADDRESS
SEX SALA
RY
SUP
ERSSN
PROJECT
PNAME
PNUMBER
PLOCATION
DNUM
Information Systems
Development
21
DNA
ME
Phase 5 binary M:N relationship
ü Include as foreign key attributes in the
primary keys of the relations that
represent the participating entity types;
their compination will form the primary key
ü Many employees works on project:
works_on – attributes: employee ssn,
project number, hours
Information Systems
Development
22
Phase 5: regular binary M:N relationship
Works_on
ESSN
PNO
HOURS
Information Systems
Development
23
Phase 6: Multivalued attribute
ü If a multivalued attribute is composite, we
include its components
ü In this case department number and
department location
Information Systems
Development
24
Phase 6: Multivalued attribute(s)
Dept_locations
DNUMBER
DLOCATION
Information Systems
Development
25
Conclusion: Relational database model, and how to
refine relations with a set of rules called the normal
forms
1.  Regular entity type
2.  Weak entity type
3.  Binary 1:1 relationship
4.  Binary 1:N relationship
5.  Binary M:N relationship
6.  Multi-valued attribute(s)
Information Systems
Development
26
Final exam
•  6th April, from 1pm to 4pm
•  19th May, from 2pm to 5pm
–  3rd possibility during next autumn?
•  The exam will include concepts definitions and an
essay
•  The other half will be applied questions i.e. you need
to draw some diagrams (e.g. use case diagram, ER
diagram, relational model or to refine relations with a
set of rules called the normal forms)
27