computer hardware presentation

2. SERIAL
NO.
NAME ID
1 SIFAT ARA SABA 21-103
2 TANIA AKTAR 21-118
3 KEYA DATTA 21-124
4 AEYSHA AKTER RANI 21-158
5 MD. IMTIAJ HOSSAIN 21-097
6 MD. RAKIBUL ISLAM 21-073
7 MD. SHAKIL AHMED 21-106
8 RUHUL AMIN 21-133
9 MD. PAPPU MIAH 21-178
10 MD. SAYED MURSALIN 21-013

3.  An entity relationship diagram shows the
relationship of entity sets stored in a
database. At first glance an entity relationship
diagram looks like a flowchart.

4.  Now we are going to design an ER diagram
for a college database. At first we have to
discuss the database of a college that is
normally seen...
1. A college contains many departments.
2. Each department has a number of sections.
3. Each department can offer any number of
courses.

5. 4. Many instructor work in a department.
5. An instructor can work only in one
department.
6. An instructor can be head of his concerned
department.
7. An instructor teaches any number of courses.
8. Each course is taught by only one instructor.
9. Each student is enlisted in only one section.
10. Each course can have any number of
students.

6.  Now we have to follow the 4 step procedures to
construct the ER diagram for the above database..
1. Identify the entities and relationship..
Here the entities are-
 Department
 Section
 Courses
 Instructors
 students

7. Department Has sections
Department Has Courses
Department Has Instractor
Students Enroll Courses
Instractor Teaches Course

8. DEPT. HAS SECTION
INSTR
UCTE
D BY
HASOFFER
COURSE
TAUGHT
BY
INSTRUC
TOR
ENRO
LLED
BY
STUDENT
S
M
1
1
N
M
N
M
M
M
M
M
1

9. 1. A department has many sections and each
department can have many sections, so the
cardinality between dept. and sections is many to
many. (M:N)
2. One dept offer many courses but one particular
course can be offered by only one department and
courses. So the cardinality between dept and
courses is one to many. (1:N)
3. A department has many instructor but one
instructor can be a member of only one
department. So the cardinality between
department and instructor is one to many. (1:N)
3. Assign Cardinalities between the
relationships:

10. 4.One course can b enrolled by many students
and one student can enrolled for may courses.
Hence the cardinality between students and
courses is many to many. (M:N)
5. One course is taught by only one instructor but
one instructor teaches many courses. Hence the
cardinality between courses and instructor is
many to one.(N:1)

11.  Department: name, location
 Ccourse: course name, course code, duration
 Instructor: ID, name, Phone number,
Designation.
 Student: ID, name, phone number
 Section: A, B, C

12. DEPT
OFFER
COURSE
ENROL
LEDBY
STUDENTS
HAS
INSTRACT
OR
HAS
SECTIONTAUGHTBY
Name Location
Dutri
on
Code
Name
Phon
e
Name
Id
Desig
natio
n
Phon
eNameId BA