Lead-In Part
An entity-relationship (ER) diagram, sometimes called an entity-relationship model, is a graphical illustration of any information technology system that helps understand the people, places, events, and objects that overall influence the given system. Most project managers create ER diagrams to analyze the existing database to improve productivity by working on the problems or mitigating the risk factors.
An Entity-Relationship diagram is a type of flowchart that is used by different domains, particularly software engineering, information systems, research, business systems, education processes, and more. By creating an ER diagram using a tool like EdrawMax, it becomes easier for system engineers to get an in-depth analysis of different information systems along with an understanding of different relational databases used in any business process.
Once you start drawing an ER diagram, you realize that this model is composed of three main elements:
- Entities: These represent objects, persons, events, or concepts in general
- Attributes: They represent the overall characteristics of an entity
- Relationship: This illustrates how two or more entities interact with each other in that particular informative system.
ER Diagram Symbols
To understand the entity-relationship diagram, we tend to work alongside ER diagram symbols. These ER diagram symbols work as a visual model of the database and help illustrate a clearer picture of the entire system.
With ER diagrams, it becomes easier for project managers to design a relational database. It should be considered here that even though an ER diagram’s symbols and notations contain three basic symbols (rectangle, oval, and diamond), they help create different ER diagrams.
Some of the most common ER diagram symbols and notations are:
- Chen ER Diagram Notations
- Crow’s Foot Notations
- UML Notations
- Min-Max Notations
- Martin ER Diagram Symbols
- ORM Diagram Symbols
- Object Relationship Symbols;
- And more
As mentioned above, an ER diagram has three major components:
1. Entities: Entities are represented by rectangles. An entity is a concept about which one needs to store information. That being said, there is also a Weak Entity, which is defined by a foreign key relationship with some other entity because of its nature that its attributes cannot identify it.
2. Relationships: Relationships are represented by diamonds. In an ER diagram, diamonds illustrate how two entities share information in one single database. It should be noted here that, in some cases, you will find that there are entities that can be self-linked.
3. Attributes: Attributes are represented by ovals. In ER diagrams, attributes are the unique characteristics of any entity — just like an employer ID at a company. There are two types of attributes:
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- Multivalued Attributes: It has more than one value. For instance, an employee can know front-end development and UX design.
- Derived Attributes: These attributes are based on other attributes. For instance, an employee’s salary would influence their bills.
How to Draw an ER Diagram Effortlessly
The need to create an ER diagram effortlessly has risen since most companies are looking for easy and affordable ways to illustrate how a computer system helps map out the knowledge of people, places, and events. In order to create an ER diagram, you need to first download and install the best ER diagram software and then follow the below-mentioned steps.
1. Download EdrawMax: EdrawMax is the best ER diagram tool in the market, as it offers many features that help draw ER diagrams effortlessly. The subsequent step that you need to take is to go to the official website and download the all-in-one diagramming tool. Once you have downloaded and installed it in your system, you can register using Google or your work email address.
On the software’s homepage, you will find 280+ diagram categories that you can instantly use. Head to ‘Software & Database’ and check ‘Database Modeling’ to access different database diagram types, like Chen ERD, Express-G, ORM Diagram, and more. Click on any of them to access built-in templates.
2. Template Access: If you are new to ER diagramming and need help in drawing the diagrams, head to the ‘Templates’ section and search for ER diagrams. From the template community section, you will find hundreds of user-generated ER diagrams that you can easily replicate. In the ‘Templates’ section, you will find ER diagram templates, like ER diagrams of Hospitals template, Forum ER diagram template, Business ER diagram template, University ER diagram template, and more.
Click on any ER diagram templates to duplicate the content as per your need.
3. Build From Scratch: If you already have the information about the relational database in detail, you can start building the ER diagram from scratch. The first thing that you need to do is to determine the entities of the ER diagram, followed by adding the attributes to these entities. Once you have identified the attributes, you can define the relationship between these entities. It is advisable to add cardinality to every relationship in your entity-relationship model.
4. Customize: Whether you are taking the help of an ER diagram template or building one from scratch, this ER diagram software lets you customize the content to the fullest. You can modify the text, change the background, update the color, style the entities, and do much more. The customization option helps in creating unique ER diagrams for your projects.
You can even import images to your ER diagram from your computer to personalize it further.
5. Export & Share: With this ER diagram software, you can export the entity-relationship model diagram into different formats, including JPEG, PNG, PDF, HTML, SVG, Docs, VSDX, and more. If you plan to share your file with your colleagues over the mail, you can use the built-in sharing option and attach the diagram via a mail copy.
Final Thoughts
As we saw in this article, an entity relationship diagram, or ERD, is a graphical illustration that showcases different entities, their attributes, and their respective relationships. ER diagrams are helpful in database designs, software engineering, academics, and more. With the right ER diagram symbols and notations, it becomes easier for the database designer to create them. If you are facing difficulties making an ER diagram, we recommend using EdrawMax. This powerful diagramming software offers free ER diagram templates, symbols, and customization options and also comes with remote collaboration, which helps draw ER diagrams effortlessly.
