Chapter 5, Problem 5.1UYK

Draw an entity-relationship diagram that shows the relationships among a database, database applications, and users.

Program Plan Intro

E-R model:

• It is a tool for creating data model.
• It is used for developers to describe the content of data model by using two functions called entities and relationships.

Entity:

• It helps the user for tracking something in database.
• Example entities in student database system are Student, Grade, Course, etc.

Relationships:

• Entities have relationships among each other.
• For example, in student database, a Student has a relationship to Major and Student has a relationship to Advisor.

Attribute:

• It used to describe the entity characteristics.
• Example attributes of student entity is Student_id, Student_name, Student_address, etc.

Identifier:

• It is an attribute or group of attribute, but its value is related with one and only one entity instance.

Example of E-R diagram:

Explanation of Solution

Entity Relationship diagram that displays relationship among the database, database application and users:

The below is the E-R diagram that shows the relationship that is laid among the database, database application and users:

User:

The person or end user that can process the application that is stored in the database.

Database application:

A database application is a collection of four elements namely forms, reports, queries and application which acts as an intermediate between the user and data of the database

Database:

Database is a collection of information that is used to store and retrieve the data. Data is organized in tables.

Explanation of the E-R diagram:

• Many user can use the database application.
  • Example of the user entity could be “students”, “faculty”.
• Many database applications can be present in a single database.
  • Example of the database application could be “Bookstore”,”Library”.
• Only one database can contain many database application.
  • Example of the database could be “studentDB”,”BookStoreDB”.
• The relationship between the user and the database application is “M:N (Many to many )relationship.
• The relationship between the database application and theDatbase is “N:1”(Many to One) relationship.