ACTIVITY REPORT

ON

CASE STUDY ON RELATIONSHIP TYPES OF DEGREE HIGHER

THAN TWO IN ER MODELLING

CONTENTS:-

DATABASE 1-2

RELATIONSHIP AND DEGREES 3-5

CASE STUDY ON UNIVERSITY DATABASE 6-7

ER DIAGRAM AND SIGNIFICANCE OF ER 8-9

DIAGRAM

NOTATIONS USED FOR ER DIAGRAM 10-11

ER DIAGRAM FOR THE UNIVERSITY DATA BASE 12

CONCLUSION 13
 Database
A database is a collection of related data. By data we mean known facts that
can be recorded and that have implicit meaning.

A database has the following implicit properties:

A database represents some aspect of the real world. Sometimes called

mini world or the universe of discourse changes to theminiworld are
reflected in the database.

A database is logically coherent collection of data with some inherent

meaning. A random assortment of data cannot correctly be referred to
as a database.

A database is designed, built, and populated with data for a specific

purpose. It has an intended group of users and some preconceived
applications in which these users are interested.

A database may be generated and maintained manually or it may be

computerized. For example, a library card catalog is a database that may
be created and maintained manually. A computerized database may be
created and maintained either by a group of application programs
written specifically for that task or by a database management system.
 ENTITY
The basic object represented in the ER model is the entity which is a
thing in the real world with an independent existence with physical
existence as person, car, house or object with conceptual existence
such as place, company, university etc.

ATTRIBUTES

Attributes are characteristic properties that describe an entity .

For ex: An EMPLOYEE entity may be described by his name ,age
,address, job, salary etc. Particular entity will have a value for each of
its attributes.

Examples for entity , attributes and values

ENTITY: Employee

ATTRIBUTE VALUE
Name Sneha
Address 2311 xxx
Age 55
Phone no 9876543247
RELATIONSHIP:
The association among entities is called a relationship.

RELATIONSHIP DEGREE:
The degree of relaionship type is the number of participating entity
types.

BINARY RELATIONSHIP:
A relationship of degree two is called binary relationship.

For ex:
 CASE STUDY ON UNIVERSITY DATABASE:

We visited Karnataka UniversityDharwad and we collected information

regarding the functioning of university.

They told us that University is high level Educational Institution in which

students study for Graduation and Post Graduation.

The jurisdiction of the university covers Dharwad, Gadag, Haveri and

Uttar Kannada districts. It has several post graduate centers. The
University is offering courses in Arts, Commerce, Law, Management,
Science and Technology.

There are 47 PG departments, 224 teachers and 4500 students (PG,

M.Phil, Ph.D).The girl students constitute 47% of the total strength.
Including PG Diploma ,M.Phil courses 6% of the students are from
outside the state.

There are 5 constitutes colleges of offering UG and PG courses.

There are 21 hostels including a working womens hostel and ladies.

These provides residential accommodation to 2600 students of UG and
PG courses. Over the last 60 years the number of affiliated colleges has
increased from a mere 34 to 250.

The university provides wide options and choices to PG courses,

diplomas and certification courses.
 There are 47 PG departments, 224 teachers and 4500 students (PG,
M.Phil, Ph.D).The girl students constitute 47% of the total strength.
Including PG Diploma ,M.Phil courses 6% of the students are from
outside the state.

There are 47 PG departments, 224 teachers and 4500 students (PG,

M.Phil, Ph.D).The girl students constitute 47% of the total strength.
Including PG Diploma ,M.Phil courses 6% of the students are from
outside the state.

We identified entity and attributes from the raw information which we

had collected from case study on university data base.

In our university database entities and attributes are:

ENTITY ATTRIBUTES

FACULTY Faculty-ID, Faculty Name, Title

STUDENT Name,Address,Bdate,Student-ID,Gender

DEPARTMENTS DepartmentName,Location

COURSES Name,Course-ID,Duration
 As our case study is on relationship types of degree higher than two so
we are focusing on ternary relationship.

TERNARY RELATIONSHIP:

A relationship of degree three is called ternary relationship.

For ex: University might need to record which faculty teaches to

students of which course.
 ER DIAGRAM

An Entity relationship model also called as Entity Relationship(ER)

diagram is a graphical representation of entities and their relationships
to each other, typically used in computing in regard to the organization
of data within databases or information systems.

An Entity is a piece of data on object or concept about which data is

stored.

SIGNIFICANCE OF ER DIAGRAM

ERD stands for Entity Relationship Diagram and it is

basically a snapshot or summary of various data structure ERD is designed to
show the entities present in a datbase are well as the relationship between
tables in that database.

VISUAL REPRESENTATION:
The foremost and most important ERD benefit is that it provides
a visual representation of the design. It is normally crucial to have an
ERD if you are looking to come up with an effective database design. This
is because the patterns assist the designer in focusing on the way the
database will primarily work with all the data flows and interactions. It is
common to the ERD being used together with data flow diagrams so as
to attain a better visual representation.
 EFFECTIVE COMMUNICATION:
An ERD clearly communicates the key entities in a certain database and
their relationship with each other. ERD normally uses symbols for
representing three varying kinds of information. Diamonds are used for
representing the relationships, ovals are usually used for representing
attributes and boxes represent the entities. This allows a designer to
effectively communicate what exactly the database will be like.

SIMPLE TO UNDERSTAND:
ERD is easy to understand and simple to create. In effect,
this design can be used to be shown to the representatives for both
approval and confirmation. The representatives can also make their
contributions to the design, allowing the possibilities of rectifying and
enhancing the design.

HIGH FLEXIBLITY:

The ERD model is quite flexible to use as other relationships can be

derived easily from the already existing ones. This can be done using
other relational tables and mathematical formulae.

The ERD thereby acts like the blueprint for the database and it allows
the creation of an accurate design that reflects the needs of the project.
 Notations

ER diagrams are drawn using the following notations:-

An Entity type is shown as a rectangular box .Entity name goes in the

box. Entity names are always singular & written in capital letters.

A Diamond represents the relationship among a number of entities

which are connected to the diamond by lines.

The attributes are shown as ovals are connected to the entities or

realationships by lines.

Diamonds ,Ovals& Rectangles are labeled. The type of relationships by

lines existing between the diamonds.

Entities is Represented by specifying the cardinality ratio of the

relationship on the line joining the relationship to the entity.
 The following notations used to draw the ER Diagram:

We are using draw.io is free online diagram software for making

flowcharts, process diagrams, org charts, UML, ER and network
diagrams.
ER DIAGRAM FOR THE UNIVERSITY DATA BASE
 CONCLUSION

In this case study we have learnt that University data base keeps track of
students and their registration as well as of the universitys course offerings.
The data base also keeps track of faculty and graduate students. The data base
maintains information on students name, students address, students id,
students date of birth, students gender and also maintains the information of
faculty id, faculty name. All faculty members are related to the academic
department with which they are affliated. Each student is related to his or her
departments. An academic department has the attributes dname ,location,
dno and is related to the faculty member whos its chairperson and to the
college to which it belongs. A course has attributes course name ,course id,
and duration.

ER Model is simple enough to communicate to the end user

the data structure required by the database yet detailed enough for the
database design to use to create the physical structure.The Entity-Relation
Model (ER) is the most common method used to build data models for
relational databases.