Draw Er Diagram for the Following Scenario

Examples

Entity Human relationship Diagram Examples

Know it All about ER Diagrams

Do you have a vast database system? Are yous having difficulty making the necessary connections betwixt different entities? Well, and so ER diagrams are here to help!

What is an ER Diagram?

An ER diagram or Entity Relationship Diagram (ERD) is a type of flowchart or graphical approach that helps you lot illustrate how different entities relate to each other. It is a standard way of modeling databases and business processes.

Now that y'all take a general understanding of what ER diagrams are, we will list a few instances where you can depict them. Equally mentioned above, ER diagrams (or ER Models) are used in database designs and business processes. Some of them are every bit follows:

• Database Design: Sometimes while altering the construction of a database, it tin can exist risky to brand such massive changes. So, ERDs are the best tool to visualize the ideas, which helps identify the mistakes and correct them before executing the changes.
• Software Engineering: For an information systems project, ERDs are the first step to determine what is required. It is besides used to model a database.
• Troubleshooting Databases: ER diagrams help yous take a complete motion-picture show of the database, which helps you easily observe the entities, their attributes, and relationships with others. This then allows you to clarify the existing database and recognize the problems quickly.
• BPR (Business Process Re-engineering): During Business Process Re-engineering, ER diagrams help you lot clarify the databases and and so model a better database setup.
• Enquiry: A lot of the enquiry is based on interlinkages and observing relationships between different entities. Thus ER diagrams come in handy in such scenarios likewise.

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ER Diagrams Examples of Common Scenarios

We mentioned a few scenarios where ER diagrams are used. At present, let's look at a few real-life examples of ER diagrams.

1. ER Diagram of Hotel Management System

The ER diagram given beneath is for a hotel management system. The diagram shows all the entities and the relationships betwixt them. The data is structured and shows all the instruments of database tables.

Entities and their Attributes

The main entities of the Hotel Management Organisation are a hotel, rooms, services, payments, bookings, and customers.

• Hotel Entity: Attributes are hotel_type, hotel_name, hotel_rent, hotel_ID and hotel_description.
• Payments Entity: Attributes are payment customer ID, payment_ID, payment_description, payment_date, payment_amount.
• Client Entity: Attributes are customer_pass, customer_email, customer_mobile, customer_ID, customer_name, customer_address.
• Booking Entity: Attributes are booking_description, booking_type, booking_ID.

All the entities are normalized, and the duplicity of records is reduced. Furthermore, there are one-to-one and one-to-many relationships.

2. ER Diagram of Database - University Database

A university database consists of all the information regarding a student. Although such a database is non suitable for a large establishment, information technology illustrates relationships that help resolve queries.

Entities and Attributes

• Pupil Entity: Attributes are a name, age, birthplace, birthday, etc.
• Form Entity: Attributes are course title, grade description, credit hours, course instructor.
• Professor Entity: Attributes are tenure status, job title, name, age.

A student enrolls in many courses, and so it's a one-to-many relationship.

iii. ER Diagram of Library Management Organization

The library management system has a database that shows the relationships between the entities such every bit a book, publisher, and fellow member. Since this is a simple arrangement, information technology has just three entities. Other systems can be more complex with a more meaning number of entities such as staff etc.

Entities and Attributes

• Book Entity: It has author, book_ID, title, toll, and availability.
• Publisher Entity: It has publisher_ID, publisher_address, and publisher_name.
• Member Entity: Information technology has member_ID, member_date, member_type, member_address, member_name, and expiry_date.

In this example, we can again see one-to-one and one-to-many relationships. A member can borrow many books, but just one reader can borrow one volume. Then, the relationship is 1: Many.

iv. ER Diagram of Online Shopping Organization

The ER diagram given below is for an Online Shopping Management System. The purpose of this ER diagram is to use a database and Java to create a proficient project.

Entities and Attributes

• Website/Application Entity: Attributes are domain name and app name.
• Customer Entity: Attributes are username, countersign, email address, mobile number, country proper noun, commune, address, C_id.
• Products Entity: Attributes are product ID, P_name, P_category, P_price, P_availability.
• Admin Entity: Attributes are username, password, A_id.
• Shopping Cart Entity: Attributes are product id, product name, total toll, billing products.
• Registration Entity: Attributes are user id, username, password, forgot password, signup.

Nosotros tin notice some relationships between the entity and its attributes, such every bit the entity mobile app and its domain proper name aspect. This shows that the projection caput will create the project based on software. Likewise, we can also notice other relationships between customers and admin, products and admin, etc.

five. ER Diagram of NoSQL Database

Given below is a template for a NoSQL database ER diagram.

Entities and Attributes

• Transaction Entity: Attributes are transaction Id, productId, Item Id, client name, and sale price.
• Customer Entity: Attributes are customer id, product id, and barcode.
• Products Entity: Attributes are product id, product name, product make, product toll.
• Cashier Entity: Attributes are cashier id, cashier name, cashier prison cell number, cashier social security number, cashier email, and cashier'southward joining date.

You lot can discover the relationships betwixt the production and customer and product and transaction. This is a ane-to-many relationship. Other relationships include cashier to transaction and transaction to the client.

half dozen. ER Diagram of One-to-Many Human relationship

Post-obit is an example of an ER diagram that is showing a one-to-many relationship.

Entities and Attributes

• Delivery Entity: Attributes are delivery ID, order ID, type, status, departure, arrival.
• Client Entity: Attributes are customer ID, phone, email, customer'southward address.
• Payment Entity: Attributes are payment id, payment date, type, order ID, customer ID, total payment.
• Guild Header Entity: Attributes are order ID, lodge engagement, club time, and customer ID.
• Order Line Entity: Attributes are order id, line id, pizza id, and quantity.
• Pizza Entity: Attributes are pizza id, name, specification, and price.

You lot tin can observe the one-to-many relationships such as lodge time of order header entity is linked to the payment type, payment date, and club id of the payment entity.

seven. ER Diagram of Banking System

The ER diagram given below is for the Bank Management System. It illustrates critical information about the banking concern.

Entities and Attributes

• Depository financial institution Entity: Attributes are banking company name, lawmaking, and accost.
• Customer Entity: Attributes are customer_id, name, phone number, and customer's accost.
• Branch Entity: Attributes are branch_id, branch name, and branch address.
• Account Entity: Attributes are account_number, account_type, and account balance.
• Loan Entity: Attributes are loan_id, loan_type, and loan amount.

Yous tin observe different relationships, such as a branch offering many loans, so one: N relationship. Other relationships such as One thousand: Due north can also be observed.

eight. ER Diagram of Infirmary Management Organization

The below ER diagram is for a hospital management arrangement. You can run across the different entities and how they chronicle to each other.

Entities and Attributes

• Patient Entity: Attributes are social security number, name, insurance, engagement of admission, date of checking out.
• Doctors Entity: Attributes are dss#, name, specialization.
• Examination Entity: Attributes are test_id, test_name, test appointment, examination time, test result.

Y'all tin observe that a doctor treats many patients, and a patient might go to different doctors. It is an M: North human relationship. Other relationships can also be observed.

Use EdrawMax for ER Diagram Creation

Drawing an ER diagram is a tiresome and lengthy process. So, we suggest that you utilise EdrawMax to ease your difficulty. EdrawMax is an excellent ER diagram software for drawing and mapping that makes the procedure shorter and quicker. Yous can use a wide variety of entity relationship diagram examples available for costless.

As the best culling to Visio, EdrawMax supports drawing entity relationship diagram, Chen ERD, Martin ERD, Limited-Chiliad, ORM diagram, database model diagram, etc. By using like shooting fish in a barrel-to-utilize drawing tools, together with many pre-fatigued ER diagram templates and more than than 6000 symbols and icons, creating ER diagrams can be amazingly fast and piece of cake.

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