Concept explainers
Draw an entity-relationship diagram that shows the relationships among a
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.
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Chapter 5 Solutions
Using MIS (10th Edition)
- A new sales ordering system needs a relational database that contains a customer table, a product inventory table, and an order table. Use a word-processing, graphics, or spread-sheet program to draw an entity-relationship diagram showing the relationships among these entities. Next, design each of these tables showing the keys and attributes to be included in each table. Include five sample records for each table.arrow_forwardUsing a graphics program, develop an entity-relationship diagram for a database application for an Internet bookstore where students buy textbooks from a salesperson and receive invoices for their purchases. Use Figure 5.5 as a guide.arrow_forwardA new sales ordering system needs a relational database that contains a customer table, a product inventory table, and an order table. Use a word-processing, graphics, or spreadsheet program to draw an entity-relationship diagram showing the relationships among these entities. Next, design each of these tables showing the keys and attributes to be included in each table. Include five sample records for each table.arrow_forward
- Design E-R diagram for a database of an Airline-System. The database must keep track of Customers and their Reservations, Flights and their status, Seat assignments on individual flights, and the Schedule and Routing of future flights. Your design should include primary-key and foreign-key.arrow_forwardWhat are the advantages of using entity relationship (ER) diagrams in database design?arrow_forwardDesign an E-R diagram for a database for an airlines system. The database must keep track of customers and their reservations, flights and their status, seat assignments on individual flights and the schedule and routing of future flights. Apply all the database design constraints as much as possible.arrow_forward
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