Database Design Project: ER Diagram for Property Management System

Desklib provides solved assignments and past papers to help students learn.

Contents
Introduction......................................................................................................................................2
Entity-Relationship Diagram...........................................................................................................3
Assumptions....................................................................................................................................3
Conclusion.......................................................................................................................................6
References........................................................................................................................................7

Introduction
The assessment is to create an ER diagram that explains the overall scenario and there are
various constraints that are added in the ER. The solution is created by the help of draw.io and
the overall diagram is attached in the file. The solution is based on the property where the
customer can own as well as rent the property as well. In the ER diagram, there are nine different
entities with a different attribute. Some attributes are primary key and some are foreign. So
overall design is created and some assumptions are also given.

Entity-Relationship Diagram
Figure 1: Diagram
Assumptions
There are various assumptions and they are listed here:

Assumption 1:
Entities that are created have various constraints like primary key and foreign keys. In almost
every entity there are primary keys that help in unique identification of the column. These
primary keys are mentioned through bold and underlined attribute (Nadarajan & Yang, 2016).
Assumption 2:
There is a multi-valued attribute named as work_type and this attribute contains multiple tasks in
one attribute like work_type will include the work related to the plumber, electrician, etc.
Assumption 3:
The entity Property is connected with entity Staff as one property can handle by multiple staffs
so they have a one-to-many relationship (Coronel & Morris, 2016).
Assumption 4:
PROPERTY_RENT entity is created as the entities CLIENT and PROPERTY were connected
with the many-to-many relationship so to remove this relationship, PROPERTY_RENT is
created and it creates the relationship with the other entities.
Assumption 5:
In the PROPERTY_RENT entity, the CONTRACT_ID is the primary as for every contract there
should be unique identification in which no duplicate entries can be created.
Assumption 6:
The entity APPLICATION_FORM is created as the OWNER will apply and fill details of the
property in the form so that customer can check the details of the property and can buy the
property (Powers, 2019).
Assumption 7:
The STAFF is specialized among two different categories EXTERNAL_WORKER and
EXTRA_WORKER. These workers perform various tasks in order to maintain property like
cleansing, electricians, etc.

Assumption 8:
One owner can give multiple properties on rent so the entity OWNER and PROPERTY_RENT
are connected with one-to-many relationship with one another.
Assumption 9:
Multiple applications are checked and supervised by the manager and the manager can supervise
the multiple staff that includes various workers.
Assumption 10:
One client can buy multiple properties so the entity CLIENT and PROPERTY_RENT are
interconnected with a one-to-many relationship with one another.

Conclusion
The above diagram covers the overall scenario with all the constraints in it. The assumptions are
explained above that include various constraints like primary keys, multi-valued attribute,
foreign keys, and every attribute has its own representation like the foreign key is in italic font
and the multi-valued attribute is in a double circle that contains multiple tasks.

References
Powers, D. (2019). Managing Multiple Database Tables. In PHP 7 Solutions (pp. 489-525).
Apress, Berkeley, CA.
Coronel, C., & Morris, S. (2016). Database systems: design, implementation, & management.
Cengage Learning.
Nadarajan, G., & Yang, C. L. (2016). Database Tables Related to F4K
Workflow. Fish4Knowledge: Collecting and Analyzing Massive Coral Reef Fish Video
Data, 104, 301.