Conceptual and Logical Database Model

Running head: CONCEPTUAL AND LOGICAL DATABASE MODEL
Conceptual and Logical Database Model
Name of the Student
Name of the University
Author’s note:

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Conceptual Model:
Figure 1: Conceptual Database Model
(Source: Created by Author)
The conceptual model visualizes the attributes, entities and relationships of a database.
The ERD is the most common and effective way of creating representing the conceptual models.
The proposed ERD holds the entities of database, attributes within the database as well as the
relationships among the database entities (Rao 2017). Only the foreign keys has been proposed

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in the conceptual entity relationship model. The conceptual model also represent the
generalization. The entity can be referred to as an object which holds information about an
element of business. Taken as an example, the entity can represent person as well as business
elements like invoice, payment. Generally an entity in the database holds a primary key that
separates a row from other rows. However, database can have entities that does not have any
primary key. These database entities are called weak entities (Coronel and Morris 2016). Weak
entities can also hold primary keys but the primary key have to be borrowed from another entity.
Taken as an example, if an entity has a primary key that is primary key of another table then also
the entity becomes weak entity.
The relationships can be referred to as the situation that is associated between one or two
elements. A relationship can be implemented in a single entity. Taken as an example, if a set of
people is working under three different leaders then self-relation would be a great way a
representing it. The relation visualizes the structure of the database such as which entity will
borrow the primary key (Connolly and Begg 2015). The relationships in an entity relationship
diagrams are one-to-one, one-to-many, many-to-one and many-to-many. The main purpose of
relationship is implementing connection between the attributes in the entire database. Without
relationship every attribute has to be included in a single entity which can raise a huge data
anomaly issues. The relation is implemented in a database while applying the normalization
techniques (Hung, van Hung and Anh 2018). For creating each new entity in the normalization
process, a new relationship is invoked between the parent entity and newly created child entity.
The proposed entity relational model has 11 attributes for the conceptual approach. The
number of entities can increase in the logical model because logical models does not support
many-to-many relationship. The generalization exists between the employees and staff,

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administrator and professor entities. The employee entity is the parent entity of staff,
administrator and professor entities. The primary key of employee entity is empNo. This primary
key is also referenced in all the three child entities. The case study suggested that professors can
also be administrator. That is why the empNo in administrator also refer to the empNo of
professor. Most of the relations in the conceptual model is one-to-many. The only man-to-many
relation exist between the student and class. This is because many student can enroll into many
classes and one class can have many student. As each staff provides academic support to many
student, staff and student have one-to-many relationship among those entities. One-to-one
relationship exists between the room and building entities.