Entity Relationship Diagram Template

Understand how the elements of your database interact with each other by using our Entity Relationship Diagram Template.

About the Entity Relationship Diagram template 

Understanding the ins and outs of a complex system is no easy feat — especially when you need to explain it to external stakeholders. 

This is where an entity relationship diagram can help. 

The entity relationship diagram outlines how entities (such as people, objects, and concepts) relate to each other in your system. It’s a logical model that makes it easier to visualize database design.

What is an entity relationship diagram? 

An entity relationship diagram (ERD) portrays relationships between entities (otherwise known as actors) in a system. Peter Chen, a computer scientist, created the concept in the 1970s. Displayed in a flow chart style, the diagram uses arrows to demonstrate how different entities relate to one another. It’s sometimes known as a logical data model, a conceptual data model, or a physical data model. 

These entity-relationship models are common in software engineering, education, research, and business information systems. They typically visualize relationships between different roles. For example, a product manager’s relationship with a developer. They also illustrate the relationship between tangible business objects, such as a product or service, as well as intangible business objects, like a backlog. 

ER diagrams are also used alongside data flow diagrams, which map out the flow of data in systems and processes. Using both of these diagram types, teams can visualize how entities relate to each other and how data moves through the system.

Read on to find out how these powerful tools can help your team. 

What is an entity relationship diagram template? 

An entity relationship diagram template is a ready-made framework for creating ERDs. You can jump straight in and use the template to outline your entities and their relationships without having to create the diagram from scratch. It saves you time better spent on more value-adding activities. Share it with other users, add comments, and amend the shapes and arrows to create the perfect diagram. 

Depending on the relationship chart maker you use, you’ll also have access to various collaborative and intuitive features to make the process easier. 

How to create an entity relationship diagram with Miro 

Making a conceptual data model is easy using Miro. Simply select this entity relationship diagram template and follow these steps:

Step 1: Identify all entities in the system. An entity is anything that you can define, such as a person, concept, or object. Start by identifying what these are in your system and outlining them in the diagram. Entities usually sit in a rectangle within the conceptual model. 

Step 2: Add meaningful names to entities. Give meaningful names to your entities so that they’re easy to understand. For example, if your entity is a person, write their name. 

Step 3: Identify relationships between entities. Draw relationships between entities with connection lines. Arrows are used to represent these relationships.

Step 4: Customize your diagram. Now, you can customize the diagram according to your needs. Add shapes, change colors, edit text, and use sticky notes. With Miro’s template, you can also upload files (such as documents and images) to clarify and enhance your template.

Step 5: Collaborate with your team. Invite your teammates to join and collaborate with you on your ERD. Any changes will be saved automatically.

Advantages of using an entity relationship diagram

There are various advantages to creating an ER diagram. These include: 

  • Simplify complex systems. ERDs allow your team to visualize how complex, interconnected entities connect and overlap in a system.

  • Easy to understand. This powerful tool is simple to use and easy to understand. You don’t need to be a software developer to create the diagram, and you don’t need any technical knowledge to understand it. 

  • Improve collaboration. If you use an online diagram, everyone can access the information and collaborate on the diagram. 

The key components of an entity relationship diagram 

There’s a lot of jargon to wrap your head around when creating a logical data model. Here, we’ll clarify some of the key components. 

  • Entity: A single entity is a definable thing, like a person or an object (it sometimes helps to think of them as nouns).

  • Entity type: An entity type is a group or collection of entities. For example, a group of students. While an entity would outline an individual student, the entity type focuses on the group. 

  • Entity set: Similar to an entity type, an entity set outlines a group of entities, but it focuses on a particular point in time. For example, a group of students on their graduation day. 

  • Entity categories: There are three main entity categories: associative, strong, and weak. An associative entity associates entities within an entity set. A strong entity is defined by its attributes, but a weak entity isn't. 

  • Relationship: The way entities relate to each other is described as their relationship. For example, if a student takes an exam, the two entities would be the student and the exam — the relationship is the act of taking the exam. Relationships are typically drawn as a diamond in a diagram. 

  • Recursive relationships: A recursive relationship appears when the same entity takes part in more than one relationship. For example, if a student is taking an exam and graduating. The entity (the student) is performing two separate actions, creating a recursive relationship. 

  • Attribute: A key attribute is a characteristic of the entity. Attributes are usually displayed in an oval within the physical model. 

  • Descriptive attribute: A characteristic of a relationship, not an entity. 

  • Multi-value and single-value: An entity can have single or multiple attributes within the physical model. These are called single-value or multi-value entities. 

  • Cardinality: Cardinal relationships are the numerical attributes of the relationship between entities or entity sets. There are three main sets: one-to-one, one-to-many, and many-many. An example of a one-to-one relationship might be a student who has one phone number, whereas a one-to-many relationship could be a student with multiple phone numbers. A many-to-many relationship could be a group of students associated with multiple phone numbers. 

When do you use an ERD? 

Here are some common examples of when to use an ERD: 

  • To educate your teammates. ERDs are powerful tools for educating your teammates on the relationship between systems or entities. 

  • To onboard new teammates. Because ERDs are visual, they’re an easy way to showcase information for new hires.

  • Whenever you need to create documentation before making a change. When preparing to change a process, it can be useful to document your existing process. By doing so, you make sure that all necessary measures are in place in case you need to return to the previous process or iterate on the current one.

Entity Relationship Diagram FAQs

What is an ER diagram (ERD)?

An ER diagram (sometimes known as a physical data model) is a conceptual model that shows how entities relate to each other in a system or database. Computer scientist Peter Chen created the idea in 1976.

What is an entity in the entity relationship diagram?

An entity is a definable thing in an entity-relationship model. It could be a person, an object, or a concept. Different types of relationships connect entities within the diagram. These connections show you how entities interact and relate to each other.

How do you draw an entity relationship diagram?

Start by identifying all the entities in your system. Once you’ve found them all and named them appropriately, you can draw relationships between them — and that’s pretty much the thick of it. When it comes to designing the diagram and using shapes, consider using a ready-made template. It’ll make the process quicker and more efficient. Take a look at the Entity Relationship Diagram template as an example. It’s intuitive, it’s easy to make changes, and you can share it with colleagues and external stakeholders.

Entity Relationship Diagram Template

Get started with this template right now.

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