ER Diagram for Online Ordering System | ERD

The entity-relationship (ER) diagram for online ordering system describes the relationships of the ordering system entities and converts them 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?

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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. It’s a straightforward automated system that allows your restaurant to accept online food orders from clients via a branded website or mobile app.

Ordering systems boosts your bottom line by expanding your target market. Customers will value it because it enables them to place orders quickly and conveniently at any time. They can also feel confident that there will be no misunderstandings when they put their orders.

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.

To build and troubleshoot relational databases, the online ordering system ER Diagram is used. It works best with DFD (Data Flow Diagram), which is responsible for data movement. Designing the database of online ordering system would be much easier with the help of ER diagram.

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 handle the data needed in managing customer and product information as well as the transactions made by the customer and seller.

The features included in the system ER diagram were the security and monitoring of the customer orders, transactions, and ordering status. These features were also listed and recorded in reports that served as the history of transactions done in the system.

Importance of ER Diagram

The importance of ER diagram for online ordering system is to help in modeling its data storage or database. It is the basis of the project’s database foundation for construction. This entity-relationship diagram (ERD) also aids in defining the data types to be stored such as their attributes and characteristics.

In addition to that, the ER Diagram also describes how an entity interacts with other entities. All other real-world projects are presented with ER Diagrams (database designs). To display the details and attributes of a data store, the er diagram for online ordering system is used in conjunction with its data flow diagram.

Entity-relationship diagrams are utilized in software engineering during the planning phase of software development. It aids in the identification of various system constituents and their interrelationships. Online Ordering System ER Diagram is also used as the foundation of the online ordering system DFD (Dataflow Diagram).

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

Based on the image above, the ER diagram for this System is the entity of the Online Ordering system database, which is presented by tables; seller, customer, products, categories, orders, deliveries, payment, and sales reports. The tables are made to meet the required specification of the system and provide much more specific details of each entity within the system.

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.

The field column presents the names of each database’s attributes, the description column gives the complete thought of each attribute, the type column is their data type and the length is for 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 has the complete description of the database and they will put this into the program storage the same as the names given to each of the tables. 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 and Cardinality

    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.

    ER Diagram Cardinalities:
    The styling of a line and its termination demonstrates cardinality and ordinality.
    The greatest number of times an instance of one thing can be related to instances of another entity is referred to as cardinality.
    While Ordinality refers to the fewest number of times a single entity instance can be linked to another.

  • Step 2: Finalize the entities included

    Start designing your ER Diagram by finalizing the entities that must be included in your online ordering system. This entity is represented by a rectangle, and you’ll want to leave plenty of room for them in future phases so you may add them to your design.

    An entity set is a group of similar entities with shared properties. A table or a table’s attribute is an entity in a database management system. As a result, by depicting relationships between tables and their characteristics, an ER diagram displays the whole logical structure of a database.

  • 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.

    The entity’s attributes were represented by ovals and can be seen in the tables of the online ordering system er diagram. These attributes can be a primary key or a foreign key in the database design of the project. Yoy ER diagram design could also be converted to the database of the system by declaring your right entities and their attributes.

  • Step 4: Describe the relationships (cardinality) between entities and attributes

    To plot relationships between the ERD you will need the entities, their attributes, and relationships. You will base the data structure from the evaluated information to have the exact Entity Relationship Diagram.

    A relationship is an association that describes how two entities interact. 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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