What is a Database? Definition, Meaning

Running head: DATABASE
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Name of the Student
Name of the University
Author Note

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Table of Contents
Extended Entity Relationship Diagram...........................................................................................2
Assumptions....................................................................................................................................3

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Extended Entity Relationship Diagram
Entity Relationship diagram represents the real world object as entities, attributes and
relationship between them. It helps in developing the conceptual structure of the database
management systems. Today’s real world problems have become more complex which cannot be
modelled by traditional Entity Relationship Diagram only. To manage the complex business
cases and structure, enhancement is done in the exiting ERD models. Complex requirements and
structured are modelled with the help of Enhanced or Extended version of the ERD.
Specialization and Generalization; Union and Category etc. are the main Features of the EERD.
Specialization uses subclasses build on the basis of the specialization and generalization is based
on generalization class. Specialization is shown with the help of ‘IS-A’ model. For example
activity is an outdoor activity and indoor activity. The generalized classes in activity. On other
hand, Instructor is a masseuse, outdoor instructor and swimming instructor. While the
generalized class is Instructor here. The min max notation is used to represent the relationship
between the entities along with the cardinality. The primary keys, entities, attributes ad
relationship is clearly represented in the ERD. The relationship is developed with the help of the
business process of the company.

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Figure 1: Extended Entity Relationship Diagram
Source: Created by author
Assumptions
In EERD, Assumptions are made for supporting the objects and structure of the design.
Assumptions are facts that may or may not be true. The facts can be related to the business
processes, technicalities, constraints, limitations etc. Business process mainly helps in defining
the backbone structure of the ERD. Assumptions help in including the criteria which is
considered during the development of the conceptual diagram. Assumptions are important for the
design, solution and architecture of the ERD. The business objects are presented in a way that it
represents the Specialization, Generalization, union or category in an ERD which makes the
Diagram enhanced. For the development of EERD of Getaway Holidays Reservation Database
System, Assumptions are described below:
i. A client can book one or more reservation for holidays.
ii. A client can book for one or more guests for a single reservation.
iii. Each single reservation is associated with only one client of the system.
iv. Each reservation can consider the past health condition of the client for selection of
activities.
v. Each reservation can have 0 or multiple activities in the package.
vi. Each reservation is accommodated to one or many rooms.
vii. Each room is accommodated for one and only one booking.
viii. Start Date of the reservation is less than End date of reservation.

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ix. Start data of the reservation is greater than the current date in system during the
reservation.
x. Each room can be one and only one type of accommodation.
xi. Each accommodation type can have 1 or more rooms.
xii. There is only one connected room to one room.
xiii. Each activity can be present in one and many reservations made by client.
xiv. Each activity is either Indoor or Outdoor activity.
xv. Each indoor activity is an activity.
xvi. Each outdoor activity is an activity.
xvii. Each outdoor activity can use one or many equipment during activity sessions.
xviii. Each Equipment can be used in one or many outdoor activities.
xix. Each equipment have one or more supplier.
xx. Each supplier can supply one or more equipment.
xxi. Each activity can have one or many instructors during client’s trip.
xxii. Each activity is supervised by one of the instructor.
xxiii. Each Instructor can instruct one or many activities.
xxiv. Each instructor is either Outdoor instructors, Masseuse or Swimming Instructor.
xxv. Each Outdoor instructor is an Instructor.
xxvi. Each masseuse is an instructor.
xxvii. Each Swimming Instructor is an instructor.
xxviii. All activities are mentioned by client only at the time of registration.
xxix. A client cannot pay partially during booking.
xxx. Client can book twice in a year to avail 10% discount and thrice for 15% a year.

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xxxi. Client can avail 5% discount if booking a trip of more than 5 days.
xxxii. Client can take parts in one or more activities.
xxxiii. Each client can choose their accommodation type and activities.
xxxiv. A supplier can also be a client to book reservation for holidays.
xxxv. An instructor can be a supervisor of the activity for a particular date and time.
xxxvi. Each floor level can have multiple rooms for accommodations.
xxxvii. Each instructor can have multiple fields of expertise.
xxxviii. Each equipment used in the outdoor activities are used by outdoor instructors.