Data Modelling & SQL Language

Running head: DATA MODELLING & SQL LANGUAGE
Data Modelling & SQL Language
Name of the Student
Name of the University
Author’s note:

DATA MODELLING & SQL LANGUAGE1
Table of Contents
Task 1: Understanding of Database.................................................................................................2
Comparison between File based System and Database System..................................................2
Characteristics of Hierarchical, Network and Relational Models:..............................................3
Hierarchical Model..................................................................................................................3
Network Model........................................................................................................................4
Relational Model.....................................................................................................................5
Top-down and Bottom-up Approaches:......................................................................................6
Task 2: Conceptual Modelling.........................................................................................................7
Task 3: Logical Modelling...............................................................................................................8
Task 4: Physical Modelling...........................................................................................................14
Create Database:........................................................................................................................14
Populate Database:.....................................................................................................................19
Bibliography:.................................................................................................................................21

DATA MODELLING & SQL LANGUAGE2
Task 1: Understanding of Database
Comparison between File based System and Database System
File based System Database Management System
It is a general, easy usage system that store all
the required files that requires less security
and constraints (Poddar, Boelter and Popa
2016).
Database Management System is mainly used
for used when the security parameters are
high.
In file based system, there are more chances
of data redundancy
In data management system, data redundancy
is found to be minimum.
Inconsistent of data is found to be minimum
to more
Data inconsistency is found to be less.
Centralization is very much tough to get. Centralization is easy to achieve.
To get an access of the physical address, user
need to get access to the required data.
User does not have any kind of idea with
respect to physical address.
Security is considered to be minimum Security is considered to be maximum.
File based system aims to store unstructured
data.
DBMS aims to store structure data.
Advantages of File based System
Saving the files and downloading them in file system is much simpler: User just need to
click as ‘Save As’ which will help them out (Scotti et al., 2016). Downloading can be easily done
by making address of the URL of save file location.
Migration of data is very much easy process: User just need to copy-paste the given
folder to desired location along with writing the permission provided in the destination.
Disadvantages of Files Based System
Loosely Packed: There are no kind of operation with respect to ACID (Atomicity,
Consistency, Isolation and Durability) with respect to mapping that highlights no kind of
guarantee (Gahi, Guennoun & El-Khatib, 2015). Scenario can easily arise when the given file is
deleted from their location in manual way.

DATA MODELLING & SQL LANGUAGE3
Low Security: User need to write permission as the given files are stored in the folder. It
is completely prone so safety issues and troubles like hacking.
File based System has certain number of limitation
i. Separation and Isolation of give Data
ii. Data Duplication.
iii. Dependency of data
Advantages of Database System
i. ACID consistency that is mainly inclusive of rollback and update of files which
stored outside the given database.
ii. Given files will be synchronized within the database and cannot be easily
orphaned that gives them tracking of their transaction.
Disadvantages of Database System
i. Memory is considered to be ineffective and all the required data goes to the RAM
(Luo et al., 2018). In RDBMS, a proper track of each of data page is maintained.
ii. Backup of data is found to be more heavy and hefty.
Limitation of Database System
More Costly: Creation and Managing of Database is considered to be bit costly in nature.
High cost software and hardware are needed in the database.
High Complexity: DBMS is considered to be bit complex which requires creating,
editing and modifying the database.
Characteristics of Various Models:
Hierarchical Model
It mainly organizes the given data into a tree- structure so that each of the record is
completely send to the single Parent or root. After that, sibling records are mainly sorted in a
proper order (Rao, 2017). This particular order is mainly used for storage of the given database.
The given model is needed for highlighting various relationship with real world. In this model,
there is a child note which come up with a single parent note. The overall efficiency of the model
is completely described in some of the real-world relationship like recipes (Kraska et al., 2019).

DATA MODELLING & SQL LANGUAGE4
The given data is organized in a tree-like structure that comes up one-to- many relation between
various type of data. The below given diagram describes the hierarchical model:
Fig 1: Hierarchical Model
(Source: Wang, Zhou & Chen, 2017)
Network Model
This particular model is completely based on hierarchical model which allow many- to-
many relationship that exist in between linked control. It merely implies on multiple number of
parent record (Sarwat et al., 2017). This particular model is based on collection of records. Each
of them comprises of single owner or even parent record where one of member is child record.
The record comprises of member or child in given set that allow the model to provide some of
the complex relationship (Poddar, Boelter and Popa 2016). This particular model was very much
popular in the era of 70s. It is mainly defined as conference of data system languages.

DATA MODELLING & SQL LANGUAGE5
Fig 2: Example of Network Model
(Source: Scotti et al., 2016)
Relational Model
It is considered to be most common kind of model which is needed for sorting data into
the required table which is known to be relation. Each of the given term comprises of columns
and rows (Gahi, Guennoun & El-Khatib, 2015). Each of the given column comprises of
attributes and entity in given question like zip code and birth date. All the given domains in a
together way is defined as a domain. In this, Attribute or even combination of attribute is
considered to be the primary key. It can be easily referred into the other table which is defined as
a foreign key. Each of the row is defined as tuple which is all about specific details of the entity
like employee in particular (Luo et al., 2018). The given module accounts for various kind of
relation that exists in between the given tables. There are various kind of relations like one to
one, one to many and many to many.