ER Modelling

ER MODELLING

TABLE OF CONTENTS
INTRODUCTION...........................................................................................................................1
TASK A...........................................................................................................................................1
Analysis of Case study.................................................................................................................1
Top- down Modelling approach to produce Entity relationship Diagram (ER)..........................1
Bottom-Up modelling approach to identify Functional dependencies........................................2
ER diagram..................................................................................................................................3
CONCLUSION................................................................................................................................4
REFERENCES................................................................................................................................5

INTRODUCTION
Entity relationship modelling also known as ER modelling is a kind of graphical
approach which is used for designing a database (Hossain, Rajan and Schwitter, 2019). It is a
high- level data model which is used for defining data elements and their relationship for a
specified software system. It helps in explaining entity types and relationship between them. This
assessment will lay emphasis upon a case study of Merrill Hand Tools Ltd (MHT) who have
decided of undertaking major systems reengineering project. In this assessment analysis of case
study has been done, top- down modelling, bottom- up modelling and ER diagram has been
developed.
TASK A
Analysis of Case study
This case study is about Merrill Hand Tools Ltd (MHT) which is a family run business in
Sheffield that manufacturers different range of hand tools from general tooling to specialist
woodworking tools and agricultural implements. Currently they have three divisions: Product
Development, Manufacturing, and Marketing and Sales and each of these divisions has a vice
precedent who report to CEO. All the three divisions are facing some kinds of issues such as:
programmer in manufacturing department can only fix superficial user interface issues and repair
corrupted data files but he cannot be a part of original program development. Their current
database has several problems such like limit to number of simultaneous users, data
inconsistencies etc. Due to this, they have decided to undergo major systems reengineering
project in which new information system division will be developed along with three existing
systems. This new department will be led by Chief Information Officer who will hire Lead
Programmer, a Database Administrator, and a Lead Analyst. CIO will be developing a data
administration plan, roadmap that documents all application programs required for supporting
corporate operations, developing and hosting a Web app, ER diagrams and data dictionaries, and
will implement planned system.
Top- down Modelling approach to produce Entity relationship Diagram (ER)
A top down approach is based on the process that can essentially breaking down of system
to gain insight into its compositional sub-system in a reverse engineering fashion (Suraprajit,
2019). By using this model, it is basically describing the overview of system which are
1