Information System Entity Relationship Computer Science Essay

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A database brings convenient to todays working area such as large business company. The main purpose of a database is just similar to handling and keep large amount of files and documents in a large cabinet. However this method takes a large space and will be complicated to control and organized. This is why a database is introduced to keep these data organized to allow users to access, retrieve, and use of the data without any hassle. DBMS or Database Management System is software that used to set up a database, creating a database requires planning and gets to know what kind of data will be imputed. Creating a database will be easier after a simple table is constructed. In this assignment, a Student Information System is used as an example to keep student information in a database.

Moreover Oracle, dBASE and Microsoft Access are example software provided by database vendor that used to create a database. Other than Student Information System as stated above, this software allows changes in database such as adding student entity relationship to expand the database. Microsoft Access is used to create Student Information System Entity Relationship(ER) because it has user-friendly interface compared to oracle and yet it is still a powerful tool to create a simple database.

Define Question 1

1.0 What is Database and why is it needed?

A database is a collection of various types of stored data so it can be used for operation purposes. These data can be organized in different modal such as hierarchical, network and relational models depend which one is suitable for that particular operation.

A database plays an important role in many fields such as large companies, colleges as well as super markets we visit daily. Most of databases are being used in large business company which they often record their purchases, sales and keep track with employees information. Database record, store and process data to generate a variety of information for decision-making at the various levels in an organization or business company. However large number of information cannot be handle by just human alone this is why a database is used to complete these tasks accurate, relevant and timely.

There are many advantages when database is used:

It helps reduces data redundancy.

Has high processing speed to manage data in a very short time.

It allows data sharing among different users.

Maintain data independence to keep database safe even if one data is corrupted.

Have better security because of different levels of access privileges controlled.

It avoids data inconsistency.

Reduces storage requirements.

A database will not run on its own without software. Similar to computer, a computer will be useless without an operating system. This is why DBMS (Database Management System) is required in order running and allows manipulation in database. DBMS is software that uses SQL (Structured Query Language) that is a programming language that manages data in a database.

SQL Manager for Oracle

1.1.0Database of a Student Information System

The concept of a database can be easily understood because it is similar if we create a table that stores different kind of information. It is encouraged to plan the database by making a simple table so that it will be easier when creating in DBMS. In this case Student Information System is created to store all students related information such as their index numbers, home addresses, gender and so on. The concept is started with record, which is a collection of related fields of an entity.

Each record consists of several data

Index Number

First Name

Last Name

Age

Gender

Address

Course

Grade

S0001

Julia

Yasmin

17

F

13 Hibiscus Road

BM

A

Student Information System in a College

Index Number

First Name

Last Name

Age

Gender

Address

Course

Grade

Fee Paid

S0001

Julia

Yasmin

17

F

13 Hibiscus Road

BM

A

Yes

S0002

Nicholas

Wong

18

M

24 Metro Street

IT

A

Yes

S0003

Niko

Bellic

18

M

53 Hove Beach

IT

B

No

S0004

David

Kim

17

M

4 Lake Garden

IT

B

No

S0005

Carl

Johnson

18

M

77 Park Lane

BM

C

No

S0006

John

Kay

17

M

22 Lin Seng Park

BM

B

Yes

S0007

Jasmine

Stewart

17

F

16 Park Lane

BM

B

Yes

S0008

Tony

Murphy

19

M

55 Brooker Road

IT

C

Yes

S0009

Tina

Shaw

18

F

31 Hibiscus Road

BM

A

No

S0010

David

Ford

18

M

28 Lake Garden

IT

C

No

Keyword: BM = Business Management, IT = Information Technology

The table above shows that all student information is recorded in detail of a college. Index Number is created to identify each student. All different single line of records are grouped together to form a 10 records table. The table is also known as file, which is a collection of related records and these data will be stored in colleges main database.

Primary Key

A primary key is similar to Internet search engine (Google), for example when you search for the word 'food, immediately all food related websites and pictures would display. Each file may need a primary key in a database, which is an important key name for searching a particular record in the file as well as identify each record uniquely within relation. Primary key can be consists of index number or name because they have their unique name or integers. However primary key cannot be 'address because the name is long. When a database grows larger, these primary keys will be very important to help user to find particular data they needed.

1.2.0The Relationship between Tables

Since the database is related to student information, this table may be shared in several departments such as casher, lecturers, class and students overall examination grade. This relationship is known as Relation Model, which is basically consists of a set of interrelated tables. Data in a relational model are stored in two-dimensional tables. Each department will have different privilege to access different type of data and only display the information they need. Below isthe shared information in several departments.

1.2.1 Casher

Colleges Casher

Index Number

Casher

Index

First Name

Last Name

Age

Gender

Course

Fee Paid

S0001

C101

Julia

Yasmin

17

F

BM

Yes

S0002

C102

Nicholas

Wong

18

M

IT

Yes

S0003

C103

Niko

Bellic

18

M

IT

No

S0004

C104

David

Kim

17

M

IT

No

S0005

C105

Carl

Johnson

18

M

BM

No

S0006

C106

John

Kay

17

M

BM

Yes

S0007

C107

Jasmine

Stewart

17

F

BM

Yes

S0008

C108

Tony

Murphy

19

M

IT

Yes

S0009

C109

Tina

Shaw

18

F

BM

No

S0010

C110

David

Ford

18

M

IT

No

Primary Key: Casher Index

The table above shows that all necessary information required in casher such as fee paid and casher index to track students that are not yet paid their tuition fee. While students addresses and examination grade are hidden to reduce complexity because it is not necessary. This is called as external view because it allows user to have own view of the database.

1.2.2 Student list in a particular course

Lecturers will have their own student list depend on which course they in charge. Since in real colleges database may consist over hundred students, working with a large table can be troublesome and complicated. To make it easy, this large table will be needed to break up into two related table, which are Business Management and Information Technology classes. This concept is called data normalization.

Business Management Course (BM)

Index Number

Examination ID

First Name

Last Name

Age

Gender

Course

S0001

E1001

Julia

Yasmin

17

F

BM

S0005

E1005

Carl

Johnson

18

M

BM

S0006

E1006

John

Kay

17

M

BM

S0007

E1007

Jasmine

Stewart

17

F

BM

S0009

E1009

Tina

Shaw

18

F

BM

Primary Key: Index Number

Information Technology Course (IT)

Index Number

Examination ID

First Name

Last Name

Age

Gender

Course

S0002

E1002

Nicholas

Wong

18

M

IT

S0003

E1003

Niko

Bellic

18

M

IT

S0004

E1004

David

Kim

17

M

IT

S0008

E1008

Tony

Murphy

19

M

IT

S0010

E1010

David

Ford

18

M

IT

Primary Key: Index Number

Students and their course can be easily indentified after the table is separated into two. We can clearly know that IT students are all male and both courses have equally five students each.

1.2.3 Students Examination Grade

Index Number

Examination ID

First Name

Last Name

Course

Grade

S0001

E1001

Julia

Yasmin

BM

A

S0002

E1002

Nicholas

Wong

IT

A

S0003

E1003

Niko

Bellic

IT

B

S0004

E1004

David

Kim

IT

B

S0005

E1005

Carl

Johnson

BM

C

S0006

E1006

John

Kay

BM

B

S0007

E1007

Jasmine

Stewart

BM

B

S0008

E1008

Tony

Murphy

IT

C

S0009

E1009

Tina

Shaw

BM

A

S0010

E1010

David

Ford

IT

C

Primary Key: Examination ID

The above table shows all students examination grade in the entire college and it is stored in Students examination database. This table is required for students certificate printout.

Overall, these are the examples of Students Information System in a college.

Define Question 2

2.0.0 Student Information System Entity Relationship(ER) model

We already know all the relationship between previous tables of Student Information System. However creating a table is just the first step for database creation. In order to make these tables and their relationship more efficient and easy organized, database software is required. Therefore these tables are needed to transfer to Microsoft Access. With Microsoft Access, information in each column can be easily created. Creating relational tables will be faster because column of data can be copied from one table to others.

2.1.0 Relationship between tables in Microsoft Access

2.1.1 Primary Key

Before tables can relate each other, a primary key is needed to declare in each table.

:Database pictures:11 Primary Key.jpg

The image above shows that primary key is declared in 'Students in Design View. A small key symbol (marked as small red circle) shows that Index Number has declared to primary key with primary key tool clicked (marked as large red circle). A particular field that needed to become primary key is highlighted and then Primary Key tool is clicked.

2.1.2 Relationship Chart

:Database pictures:1 Relationship.jpg

Tables must link correctly in order to view their relationship. Primary Keys are linked to another tables, for example if we compare 'Students table with 'Casher table, 'Casher Index will become primary key while 'Index Number becomes foreign key. Note that small key symbol represents which data is primary key.

Creating relationship between tables is easy because Microsoft Access has a good user-friendly interface, just simply drag a data from one table to others and the relation line will appear like the image above.

2.1.3 Relationship between Students and Casher

Students

:Database pictures:2 Students.jpg

The Student Information System is recorded into Microsoft Access as shown in image above. These information consists of students index number, which is an unique code that identifies each students. Other information such as First name, Last name, Age, Gender, Addresses and so on are also recorded inside this table.

Casher

:Database pictures:3 Casher.jpg

The data in Casher table has created to record students fee paid. Some field such as Index Number and Course are shared together with Student table.

Relationship between Students and Casher

:Database pictures:7 Students Drop.jpg

The table above shows the relationship between Students and Casher. From the first record we can clearly see Julia Yasmins casher index, course and her fee payment. While the last record we can identify that David Ford is in IT course and he is not yet pay his fee.

2.1.4Relationship between Students Course and Students Examination

Business Management Class

:Database pictures:9 BM Students Drop.jpg

Information Technology Class

:Database pictures:10 IT Students Drop.jpg

Business Management and Information Technology classes are separated into two different tables. These tables are also linked together with Students Examination Grade, which is to reveal their examination grade when it is opened. A drop down table from the tables above show that students examination grade is revealed.

Two different dropdown tables is shown (marked as red border), when we look at the Information Technology Class. We can easily identify Nicholas Wongs examination ID, which is E1002 and gets grade 'A in examination. Similar to Tony Murphy, which has examination ID of E1008 and gets grade 'C in the examination.

Students Examination Grade

:Database pictures:4 Examination.jpg

The table above shows the entire examination grade among every student.

Conclusion and Recommendation

Information is an important resource in any organization and it must be properly managed. Database plays an important role because it allows information to be stored and organized in good manner. To handle large amount of information such as Student Information System, creating several tables is required to store different data such as name, index numbers, age and so on. Creating a database also requires knowledge on how data relate each other and their model. Learning Microsoft Access will be a good start for a beginner to learn and practice how database works even though it is not powerful enough compared to other database management software.People with knowledge of database will have better job opportunity because most large company will hire them.

Bibliography

Oppel Andy, 2009, Database a Beginners Guide, Second Edition, McGraw-Hill Professional Publishing, USA………pg 23

P.Sellappan, 2002, Information Technology in Business, Fourth edition, Federal Publication SdnBerhad, Malaysia

James L. Johnson, 1997, Database Models, Languages, Design, ???, Oxford University Press Inc, USA

Shelly Vermaat, 2009, Discovering Computer 2009, Complete Edition, Shelly Cashman Series, United States of America

http://www.filetransit.com/images/screen/2935188e684b1f718eecbf92de0bdfd6_EMS_SQL_Manager_for_Oracle.gif

http://databases.about.com/cs/administration/g/primarykey.htm

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