ER Diagram for Online Ordering System

The online ordering system’s entity relationship (ER) diagram translates system entities into a database. This describes the logical structure of the system’s database or data storage. It is done by identifying the online ordering process entities, their properties, and the interactions between them.

The database design is sketched out using online ordering system ER diagram. This database sketch becomes the actual basis of the system’s data storage that will serve as data and source.

Online Ordering System ER Diagram: Details

The table shows the overall description of the ER Diagram for Online Ordering System. It has a complete overview of the project’s information.

Name:Online Ordering System ER Diagram
Abstract:The online ordering system ER diagram depicts the relationship between various entities. It can be thought of as a blueprint for your system (project) structure. 
Diagram:ER Diagram is also known as Entity Relationship Diagram
Tools Used:Diagraming tools that provide ER diagram symbols.
Users:Food Stand and Restaurant Owners and Customers.
Online Ordering System ER Diagram: Details

What is an Online Ordering System?

The ordering system is the machine like aspect of inventory management. These are the programs that convert forecasts, actual orders, safety stock, and order quantities into purchase orders or production orders. A simple automated system lets your business accept online meal orders via a branded website or mobile app.

What is an ER Diagram?

The ER Diagram is referred to as the online ordering system database design. This ER Diagram is the graphical depiction of relationships between all the entities involved in the system. Its major components are Entities, Attributes, and Relationships.

Online Ordering System Database Design

The online ordering system database design was made based on online ordering requirements. The system can encode customer information. Online Selling admin can have access to the customer status and information for the important transactions. They can manage customer and product data and customer seller transactions.

Importance of ER Diagram

The importance of ER diagram for online ordering system is to help in modeling its data storage or database. The ER Diagram also describes how an entity interacts with other entities. All other real-world projects are presented with ER Diagrams (database designs). The online ordering system’s er diagram and data flow diagram illustrate a data store’s information and attributes.

Entity Relationship Diagram for Online Ordering System

ER Diagram of Online Ordering System shows the system entity relationships in each entity and their supposed functions in each relationship.

Online Ordering System ER Diagram
Online Ordering System ER Diagram

The online ordering system database’s ER diagram includes tables for seller, customer, products, categories, orders, delivery, payment, and sales reports. The tables meet the system’s requirements and provide detailed information about each entity.

Online Ordering System ER Diagram Tables

These tables below provide the complete database table details such as Field NameDescriptionsdata types, and character lengths. Each of these tables represents the characteristics and the attributes of data storage.

Field provides each database’s properties, description explains each, type lists their data type, and length lists their character lengths.

Table Name: Customer

customer_ID (PK)Customer IDInt11
nameCustomer NameVarchar255
contact_addressCustomer ContactInt11
addressCustomer AddressText
emailCustomer EmailVarchar255
Table Name: Customer

Table Name: Categories

category_ID (PK)Category IDInt11
category_nameCategory NameVarchar255
category_typeCategory TypeVarchar255
Table Name: Categories

Table Name: Orders/Reservation

order_ID (PK)Order IDInt11
customer_ID (FK)Customer IDInt11
order_dateDate of OrderDate
Table Name: Orders/Reservation

Table Name: Deliveries

acc_ID (PK)Account IDInt11
customer_ID (FK)Customer IDInt11
delivery_dateDate of DeliveryDate
Table Name: Deliveries

Table Name: Products

product_ID (PK)Product IDInt11
category_ID (FK)Category IDInt11
product_nameProduct NameVarchar255
Table Name: Products

Table Name: Seller

seller_ID (PK)Seller IDInt11
product_ID (FK)Product NameInt11
seller_nameSeller NameVarchar255
Table Name: Seller

Table Name: Payment

payment_ID (PK)Payment IDInt11
customer_ID (FK)Customer IDInt11
payment_dateDate of PaymentDate
Table Name: Payment

Table Name: Sales Report

report_ID (PK)Report IDInt11
customer_ID (FK)Customer ID Int11
order_ID (FK)Order IdInt11
product_ID (FK)Product IdInt11
payment_Id (FK)Payment IdInt11
Table Name: Sales Report

The tables given will be the basis for developers on how would they design the online ordering database. It contains the whole database description and will be stored in the software along with the table names. They will create a database with the attributes given as well as the value of each attribute.

Online Ordering System ER Diagram [PDF]

The ER Diagram for Online Ordering System PDF provides the information explaining the concepts of the project database. You may apply this information to your capstone project. You can also use it directly or modify its content depending on your project’s requirements.

How to create ER Diagram

Time needed: 5 minutes.

Steps in building the ER Diagram for Online Ordering System with Cardinality Ratio.

  • Step 1: Familiarize the ER Diagram (Entity Relationship Diagram) Symbols

    Entity Relationship Diagram – shows the structure of data types in a project. It uses symbols to clarify its parts and relationships. Their symbols and applications must be familiarized before you build the ER Diagram.

    ER Diagram Symbols:
    Fields: Fields are the parts of a table that define the entity’s characteristics. In the database that the ERD models, attributes are commonly thought of as rows.
    • Keys is a technique to categorize data qualities. It is used to organize ER diagrams and assist users in modeling their databases to ensure that they are efficient. This is also used to connect different tables in a database.
    – Primary Key: identifies a single entity instance which means a unique attribute or set of attributes.
    – Foreign Key: is produced when data attributes have one too many relationships with other entities.

  • Step 2: Finalize the entities included

    Start designing your ER Diagram by finalizing the entities that must be included in your online ordering system. Leave plenty of room in future phases to add this rectangle to your design.

  • Step 3: Add the attributes of each entity

    After finalizing the entities, think about the qualities you’ll need to characterize each entity. The details of the various entities outlined in a conceptual ER diagram are supplied as attributes. Characteristics of an entity, a many to many relationship, or a one to one relationship are all examples of attributes. Multivalued attributes can be assigned to several values.

  • Step 4: Describe the relationships between entities and attributes

    At the connector’s endpoints, the cardinality is indicated by a crow’s foot. One-to-one, one-to-many, and many-to-many are the three most common cardinal relationships. It’s the maximum number of times an instance of one entity can be linked to instances of another entity.


You need to know the diagrams used to design and develop the Online Ordering System. That is to help you create a fully-functional system with the use of ER Diagram. Creating it will help you perceive the back end of the software. This will hold all the data that’ll enter and exit the system.

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