Database Design Concepts: A Comprehensive Guide for Mobile Repair Agency

This report delves into the fundamental concepts of database design, focusing on the creation of a relational database for a mobile repair agency. It explores key issues and applications of databases within organizations, analyzes database design techniques and methodologies, and demonstrates the practical implementation of a fully functional database. The report covers entity-relationship modeling, normalization, database development cycles, and user and technical documentation, providing a comprehensive guide to database design principles.

Database Design Concepts

Contents
Introduction:....................................................................................................................................5
LO1 Ba able to analyses the function of database and data management systems.........................6
1.1 Analyses the key issues and application of database within organizations...........................6
1.2 identify the functions of the database and database management system:............................9
LO2 Be able to analyses database design techniques and methodologies.....................................10
2.1 Analyze database developmental methodologies................................................................10
2.2 Discuss the role of entity-relationship modeling and normalization in database design:....13
LO3 Be able to design and create a database................................................................................18
3.1 Apply a database developmental cycle to a data set.......................................................18
3.2 Design a fully functional database containing inter-relational tables and a user interface..19
3.3 Evaluate the effectiveness of a database solution and suggest methods of improvement...26
LO4 Be able to demonstrate the functionality of a database........................................................28
4.1 Demonstrate the database design to assessors.....................................................................28
4.2 Create a supporting user and technical document for a database........................................29
Conclusion:....................................................................................................................................33
References......................................................................................................................................34

Table of Figures
Figure 1: Railway reservation system..............................................................................................7
Figure 2: Library Management System...........................................................................................8
Figure 3: Banking............................................................................................................................9
Figure 4: Entity-Relationship Diagram.........................................................................................13
Figure 5: Relational Diagram........................................................................................................15
Figure 6: Design of Company table...............................................................................................20
Figure 7: Table of company table..................................................................................................20
Figure 8: Output of company table................................................................................................20
Figure 9: Design of customer table................................................................................................21
Figure 10: Table of customer table................................................................................................21
Figure 11: Output of customer table..............................................................................................21
Figure 12: Design of Device table.................................................................................................22
Figure 13: Table of device table....................................................................................................22
Figure 14: Output of Device table.................................................................................................22
Figure 15: Design of engineer table...............................................................................................23
Figure 16: Table of engineer table.................................................................................................23
Figure 17: Output of engineer table...............................................................................................23
Figure 18: Design of payment details table...................................................................................24
Figure 19: Table of payment details table.....................................................................................24
Figure 20: Output of payment details............................................................................................24
Figure 21: Design of repair details table........................................................................................25
Figure 22: Table of repair details table..........................................................................................25
Figure 23: Output of repair details table........................................................................................25
Figure 24: Design of supplier table...............................................................................................26
Figure 25: Table of supplier table..................................................................................................26
Figure 26: Output of supplier table................................................................................................26
Figure 27: Database Design...........................................................................................................29
Figure 28: Company Table............................................................................................................30
Figure 29: Customer Table............................................................................................................31
Figure 30: Device Table................................................................................................................31

Figure 31: Engineer Table.............................................................................................................31
Figure 32: Payment Details Table.................................................................................................31
Figure 33: Repair Detail Table......................................................................................................31
Figure 34: Supplier Table..............................................................................................................32
Figure 35: Company Table Design View.....................................................................................32
Figure 36: Customer Table Design View......................................................................................32
Figure 37: Device Table Design View..........................................................................................33
Figure 38: Engineer Table Design View.......................................................................................33
Figure 39: Payment Table Design View........................................................................................33
Figure 40: Repair Table Design View...........................................................................................33
Figure 41: Supplier Table Design View........................................................................................34
Table of Tables
Table 1: User Documentation........................................................................................................30

Introduction:
Mobile repair agency (MRA), is a growing mobile repair company in London. It requires a
relational database to maintain the various data of the company. This database will contain
various details like products details, its category, customer details, mobile repair details and
many more. This report will contain the relationship diagram of the following company. The part
first of the report will include the function of the database with data management and key issues.
The second part will include the database design and various methodologies to develop the
database. The entity relationship term with normalization will also discuss in this part. Next part
is practical implementation part of the report which has the database development cycle with the
user interface and various methods to improvements. The last section of the report will contain
the database design and user and technical documentation for a database.

LO1 Ba able to analyses the function of database and data management
systems
1.1 Analyses the key issues and application of database within organizations
The database is the collection of various types of information which is easy to organize and
access and database management is the software which used to create and manage this database.
There are various key issues of the database which is required to remind for an organization
before creating a database. The key issues are like,
Scalability: The scalability found in almost every application and services which are based on the
web. The scalability is affected by the cataloguing components, operating systems, database
architecture and hardware configuration.
Changing landscape: The developers and organizers are constantly changing the landscape from
SQL to Oracle and then Oracle to DB2. There are so many versions of each database which
make it complex and impact the skills, policies and other areas.
Increasing the data volume: Increasing the data volume is affect the query performance, back and
recovery, increase CPU requirement and maintenance timeframes.
Data security: The big amount of data facing this problem mostly. This issues can be maintained
by its original data source with API and web services methods (bain, 2008).
Database application: database applications are computer software and programs which used to
manage and collect the information from a database system. Almost every business has its own
database to manage the records on platforms like Oracle, Microsoft Access, SQL server and
many more. There is the various application of database like banking, education, transport and in
many more. Some other applications are like query process and management, user-friendly,
integrity and security of data with data sharing. The other applications where use the database are
like railway reservation system, banking system education and library in the education sector
(Singh, 2018).

Railway reservation system: it keeps the record of ticket booking record of the passenger as well
as train status with its arrival and departure time.
Figure 1: Railway reservation system
Source: (Roberthempsall, 2011)
Library management system: it keeps the records of books with issues date, the name of the book
with its author name and availability.

Figure 2: Library Management System
Source: (Dykstra, 2014)
Banking: the records of thousands transaction with bank customer details and record of money
send and receive.
Figure 3: Banking

Source: (Shelton, 2017)
1.2 identify the functions of the database and database management system:
The database management has three elements which are:
 Physical database: the collection of files which makes data.
 Database engine: it is used to access and modify the database content.
 Database scheme: the logical structure specification of stored data in the database.
The file system is also a term of the database which includes spreadsheets, word documents,
photographs and presentation files. These all structure can be created by the user as required.
This types of system are known as file system and used for the individual system user.
There are various operations can perform in a database system like, create, edit the database,
update and delete the database. Save and retrieve operations can be performed after creating the
database. Database management system provides some other function of a database:
 Concurrency: a database can be accessed by multiple users at the same time.
 Data manipulation: this process is defined to creating the database and perform the
operations like, insert, edit and delete. These three functions handle the data manipulation
needs, which types are plashed and unlashed.
 Back up & Recovery: for maintaining the data of the organization it is required to take
backup process.
 Security: require to know the security guidelines for user rights.
 Data description: data dictionary is used for access the data description.
 Integrity: the structure of the database and its guidelines support to improve the data
integrity (Study, 2018).
Advantages and disadvantages of the database:
Advantages:
 The term centralized, control the data with avoiding duplication of data and reduce total
data storage. Also, ignore the extra process of and required only necessary data to store.

 The sharing of data is allowed for control of any application program. Control the data
integrity to contain consistent and accurate data.
 Data security is important for an organization to prevent an access by any unauthorized
person. It includes proper authentication process to access the database and check the
user before permitting to access the sensitive data. Various level of security implemented
for making secure the confidential data.
 Data independence has two types in a database, logical data independence and physical
data independence. A physical term used to change in the physical storage device. The
logical term is used in the application program to not change its existing fields by add or
delete any item from it. Changes can apply to a conceptual schema with the effect the
existing schema.
Disadvantages:
 The database management system is costly to purchase and develop in terms of software
and update in terms of hardware programs.
 It is required to process continuously of some terms like sharing of data, security of data
with integrity.
 The database might fail if duplication process is not working and backup-recovery
operation are costly and complex for every database (Tiwari, 2016).

LO2 Be able to analyses database design techniques and methodologies
2.1 Analyze database developmental methodologies
The database development methodologies used to build the database by using the client
requirement. The methodology has various phases to from requirement to design method, and
implementation, testing and documentation. The database methodology is divided into some
types like, conceptual, logical and physical database design. Here we discuss the steps of the
creating the database which starts requirement to the user and technical documentation.
Requirement analysis: the requirement analyses of mobile repair agency is to create a relational
database to maintain the company records of customers, categories, repair and services. The
customers register themselves to the database with using information like first name, last name,
date of birth, email, contact number and address. Some entities also need to create like, suppliers,
mechanics for repair mobile and create a relationship between the attributes of the relationship.
Design methodology: the methodology for the database includes some process like techniques,
tool, procedure and documentation to help in design methodology. It includes various stages
which help the designer to design the database as well as to manage and control the database.
Here are some types of design methodology:
 Conceptual ER: conceptual entity relationship diagram is the combination of entities,
relationship and attributes. The conceptual includes construction process of a model and
its deals with the task and with the user. During the process of data modelling, it follows
a prearranged methodology. Data models are represented by the figures and create a data
dictionary (W3schools, 2018).
 Logical ER: the logical entity relationship method includes the relation in the designs.
The logical methodology obtains and authorizes the relation between using normalization
process. It validates the relations and checks integrity control with its limits (W3schools,
2018).
 Physical ER: the physical entity relationship methodology is used to implemented logical
design into physical design. The terms of logical design like entity, attributes, constraints
and relationship translate into physical database design. Physical design includes the

description of execution which defines the base relation. The step of implement physical
methodology is designed base relation with the representation of data and design general
constraints (W3schools, 2018).
Implementation: there are so many tools and software to create and implement a database for an
organization like MS Access, SQL, Oracle and many more. Here I used SQL for creating and
implement the database for mobile repair agency. In the process of implementation, the tables
and queries are going to create. The table is created in the SQL database as per user requirement
and creation of entities and their attributes. These table’s data hold the primary key and foreign
key as the representation of the relationship between attributes. Joins are used to combine two or
more than two tables in SQL. Another terms query are used in the creation of SQL database. The
query is a code in SQL which used as a command form in the SQL to perform any operation or
task. The most used queries in SQL are, Select, Update, Delete and Insert.
Testing: database testing is the layering process which includes layers like, user interface, data
access layer, business layer and many more. There are various terms which include the testing of
database like, black box, white box, validation, referential integrity and others.
 Validation: validation process is used to check the information which enters by the user
or developer into the database. There are some validation methods which used for
validation of data like, range check, length check, format check, type check, drop down
check and presence check (computerscience, 2018).
Referential integrity: This term is used to define the relationship between tables. Each table of
database holds a primary key which used in another table to create a relationship. The primary
key which appears in another table of the database, known as a foreign key. A foreign key is
used as join to merge two tables and create dependencies between the tables (ibm, 2018).
Maintenance: Maintenance required for the database of the mobile repair agency and provide
tanning of database to the staff members of the organization and do regular maintenance of the
hardware and update the software tools. Download the latest version software and use the latest
technology hardware system for the database as well as provide training to the staff.

2.2 Discuss the role of entity-relationship modelling and normalization in database
design:
Figure 4: Entity-Relationship Diagram
Entity-relationship modelling: in the software development, the representation of data
relationship is completed by a conceptual and theoretical way, which is known as an entity-
relationship model. This database technique is used to generate the visual representation and
abstract diagram with using system data to design a relational database. The entity-relationship
model is also used to graphically represent the relationships to create the database. Here are the
terms of the entity-relationship model.
Entity: an identifiable object of the real world which is either inanimate or animate, like, teacher,
courses, class form a school database. Each entity has attributes or properties to providing their
identity. The collection of entities call entity set. This set of entity contains attributes with
entities and their values. The entities of the Mobile repair agency are customers, company, repair
details and engineer.

Attributes: the representation properties of the entities called attributes. These attributes contain
values like name, age, class and many more. In the Mobile repair agency, there are many
attributes of each entity and the types of attributes are as follows:
 Simple: values which cant divide any more like, phone number.
 Composite: the combination of more than one simple attribute is a composite attribute.
 Derived: this types of the attribute do not exist in the physical database and the values
derived from another attribute which present in the database.
 Single-value: it holds the single value as an attribute.
 Multi-value: multiple values are contain by the multi value attribute.
Keys and entity set: the collection of attributes are called as keys which has three types, super
key, candidate key and private key.
Relationship: the connection of entities are called relationships. The attributes are also known
as descriptive attributes. There is some degree of attributes like binary-degree 2, ternary and n-
ary or degree. Here are some types of the entity like one to one, one to many, many to many and
many to one (tutorialspoint, 2018).

Figure 5: Relational Diagram
Normalization: a technique which used to organize the data into the database. The normalization
technique is also decomposed the database tables to remove the data repetition or data
redundancy and some undesirable characteristic like deletion, update and insertion anomalies.
The normalization has some types which discuss below with the data of Mobile repair agency.
The types of normalization are discussed follows with using the entities and attributes of the
MRA database (study tonight, 2018).
1NF (First normal form):
It contains single value and the values of all columns have the same domain.
Entity Name: Supplier
Sup Id Sup Name Sup
Address
Contact
No.
Email Parts of
supply
………
……… Com Id Location Suppliers Engineers Stock ………
……… Sup Id Eng Id Device Id Device
Name
Device
Type
………

……… Description
of repair
Cost of
repair
Cus Id Payment Id Payment
Mode
………
……... Payment
Date
Device Id Repair Id Cus Id Eng Id ………
……... Eng Name Contact
No.
Email Address Cus_Id ……..
……... First Name Last Name Date of
birth
Address Contact
Num
……..
……... Email Repair Id Device
Name
Date of
Repair
Cost of
Repair
……..
……... Delivery
Date
Device Id Eng Id
2NF (Second Normal Form):
Use the table of first normal form and not contain partial dependency.
Entity Name: Supplier
Sup Id Sup Name Sup
Address
Contact
No.
Email Parts of
supply
………
……… Com Id Location Suppliers Engineers Stock ………
……… Sup Id Eng Id
Entity Name: Device
Device Id Device
Name
Device type Description
of repair
Cost of
repair
Cus Id ……..
……… Payment Id Payment
Mode
Payment
Date
Device Id Repair Id ………
……... Cus Id Eng Id Eng Name Contact
No.
Email Address
Entity Name: Customers
Cus_Id First Name Last Name Date of
birth
Address Contact
Num
……..
……... Email Repair Id Device
Name
Date of
Repair
Cost of
Repair
……..
……... Delivery
Date
Device Id Eng Id

3NF (Third Normal Form):
Use the table of second normal form and remove the transitive dependency.
Entity Name: Supplier
Sup Id Sup Name Sup Address Contact No. Email Parts of repair
Entity Name: Company
Com_Id Location Suppliers Engineers Stock Sup Id Eng Id
Entity name: Device
Device Id Device Name Device Type Description of
Repair
Cost of repair Cus Id
Entity name: Payment Details
Payment Id Payment
mode
Payment date Device Id Repair Id Cus Id
Entity name: Engineers
Eng_Id Eng Name Contact No. Email Address
Entity name: Customers
Cus_Id First name Last name Date of
birth
Address Contact
Num
Email
Entity name: Repair Details
Repair Id Device
name
Date of
repair
Cost of
repair
Delivery
date
Device Id Eng Id

LO3 Be able to design and create a database
3.1 Apply a database developmental cycle to a dataset
A database development cycle include some steps like,
 Database planning
 System definition
 Requirements analysis and collection
 Database design
 Application design
 Prototyping
 Implementation
 Data loading and conversion
 Testing
 Maintenance
These are the steps of database cycle which use in database form creation to maintenance. In this
database, I created a database for mobile repair agency with the use of SQL application. SQL is
structured query language which use to manipulate and access the database. It is an (American
national standards institute) ANSI standards. With the use of SQL, the user can do execute the
queries, retire the data from the tables, do some functions on database like, insert the data, update
the data, create a new database, delete the data or record and many other operations.
I create tables in SQL database on user requirement, these are suppliers, device, company,
engineers, payment details, repair details and customers. The data inserted into the tables of the
database through the queries or directly. Insert query used to insert the data into the database.
Other queries which used for changes in data are, update query for update the data and delete
query for delete the data from the database (www2, 2018).

3.2 Design a fully functional database containing inter-relational tables and a user
interface
The database of MRA (mobile repair agency) is successfully completed on SQL server
management. 7 numbers of tables are created in this database. Here is upload the design view of
each table as well as table view and output of each table.
Company:
Design of company table:
Figure 6: Design of Company table
Table of company table:
Figure 7: Table of company table
The output of company table:
Figure 8: Output of company table

Customers:
Design of customer table:
Figure 9: Design of customer table
Table of customer table:
Figure 10: Table of the customer table
The output of customer table:
Figure 11: Output of customer table

Device:
Design of Device table:
Figure 12: Design of Device table
Table of Device table:
Figure 13: Table of the device table
The output of device table:
Figure 14: Output of Device table

Engineer:
Design of engineer table:
Figure 15: Design of engineer table
Table of engineer table:
Figure 16: Table of engineer table
The output of engineer table:
Figure 17: Output of engineer table

Payment details:
Design of payment details table:
Figure 18: Design of payment details table
Table of payment details table:
Figure 19: Table of payment details table
Output of payment details table:
Figure 20: Output of payment details

Repair details:
Design of repair details table:
Figure 21: Design of repair details table
Table of repair details table:
Figure 22: Table of repair details table
Output of repair details table:
Figure 23: Output of repair details table

Supplier:
Design of supplier table:
Figure 24: Design of supplier table
Table of supplier table:
Figure 25: Table of supplier table
Output of supplier table:
Figure 26: Output of supplier table

3.3 Evaluate the effectiveness of a database solution and suggest methods of
improvement
The effectiveness of database:
The completed database of MRA (mobile repair agency) has all the tables with their output
results and design view and these all things are uploaded in above section. In the section
effectiveness of database, a relational database can develop many database methods for
accessing the data and records. To create a database on SQL, it is required to have the knowledge
of SQL. Some key areas in which the effectiveness of database is applied, these are:
 Data and log file management
 Index fragmentation
 Corruption detection
 Statics
 Backups (Microsoft, 2008)
Methods of improvements:
 Each database is required for improving after some time. These changes of improvements
are applied due to changes in technology. As the new technology launch, companies are
required to change the protection of their database in any cases. So here I am discussing
some methods of improvements to the database.
 The first step for database improvement is to check the database server. The database
server must have sufficient resources includes memory, disk space and CPU. Here the
CPU take the load of the server and the used memory does not affect the additional
memory which required further for installation of more function.
 Next one is to take the permission of accessing the database. It is required to know the
application on which the database is working or required to access. After knowing the
database application required and check the services of the database.
 If database services are going in bad mode than check the service’s communication with
the database. Check the execution of queries and executed request. It is required to keno
to know the issue of the database and check the reduce the number of queries for
improvement of the database.

 Check the number of connections on a database with the server. And finally check all
hardware like cables, routers for improvement in the network (Goodwell, 2014).

LO4 Be able to demonstrate the functionality of a database
4.1 Demonstrate the database design to assessors
Company
Com_Id
Location
Suppliers
Engineers
Stock
[Sup Id]
[Eng Id]
Customers
Cus_Id
[First name]
[Last Name]
[Date of Birth]
Address
[Contact Num]
Email
Device
Device_Id
[Device Name]
[Device Type]
[Description of repair]
[Cost of repair]
[Cus Id]
Engineer
Eng_Id
[Eng Name]
[Contact No.]
Email
Address
Payment Details
[Payment Id]
[Payment Mode]
[Payment Date]
[Device Id]
[Repair Id]
[Cus Id]
Repair details
[Repair Id]
[Device Name]
[Date of repair]
[cost of repair]
[delivery date]
[Device Id]
[Eng Id]
Supplier
[Sup Id]
[Sup Name]
[Sup Address]
[Contact No.]
Email
[Parts of supply]
Figure 27: Database Design
The above database design is creating using the database tool SQL server management studio.
Create attributes and entities and make relation among them in SQL tool. Define primary and
foreign key in the tables and create relation database.

4.2 Create a supporting user and technical document for a database
The documentation is a set of documents which includes all the process from start a task to end a
task. It has the information regarding financial and commercial. Documentation process has two
types of it. User and Technical.
User Documentation:
The user documentation of MRA (mobile repair agency) includes the purpose of the
documentation that is the MRA required a database to maintaining the records of its customers.
The agency includes the various category of the mobiles as well as the details about the repair,
engineer, customers and many more. The user also wants to add the details about parts of repair
with suppliers and create an ER diagram with normalization. Here the table view of database
tables is included in this part.
Table 1: User Documentation
Characteristic
s
Explanation
Client Design relational database for MRA which repair the mobiles
and other electronics. The staff members of the company are,
engineers, suppliers, and customers.
Client-
Requirements
The client wants a relational database to maintain the records of
his customers.
Application-
Limitations
Includes all the members and contain all the devices.
Figure 28: Company Table

Figure 29: Customer Table
Figure 30: Device Table
Figure 31: Engineer Table
Figure 32: Payment Details Table
Figure 33: Repair Detail Table

Figure 34: Supplier Table
Technical Documentation:
The technical document contains the technical terms like architecture, handling, functionality
and some others. The technical documentation required to contain some terms like efficiency,
corporate design, stay up to date with new technologies. The technical documentation includes
the design view of the database tables.
Figure 35: Company Table Design View
Figure 36: Customer Table Design View

Figure 37: Device Table Design View
Figure 38: Engineer Table Design View
Figure 39: Payment Table Design View
Figure 40: Repair Table Design View

Figure 41: Supplier Table Design View
Conclusion:
I successfully designed relational database for Mobile repair company which includes various
tables in the database. These tables contain different fields on user requirement. The database is
created on SQL server management studio. The design view with a table view and output images
are uploaded in this report. The first part has the issues and application of the function of the
database. Send section contains the methodology with entity relationship team and diagram
along with a relational diagram. The database development cycle explained in next section with
all the images of the database. Improvement methods and user and technical documentation is
the last part of the report.

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