ER Diagram Generator: Describe It, Get an Editable ERD

An entity relationship diagram describes the data a system stores. Entities become tables, attributes become columns, and relationships show how rows in one table refer to rows in another. The crow's foot symbols at each end tell you whether a side is one or many, and whether it is optional.

Because it sits between the idea and the actual database, the diagram is where most design mistakes are cheapest to fix. That is why courses ask for it and why teams review it before writing migrations. An ER diagram generator speeds up the drawing so you can spend the time on the design itself.

Name the main things the system keeps track of and how they relate. Sentences such as "customers place orders" or "each order contains many products" are enough for the model to find entities and cardinality. Mention anything unusual, like an item that can belong to several categories.

If you already know some columns, list them; otherwise the ER diagram generator fills in typical ones. Keep each description to one system. For a large project, generate the core tables first and add the rest later with AI edits, which keeps the layout readable.

Read the preview the way a reviewer would. Does every table have a primary key? Does every foreign key point to the right table? Are many-to-many relationships resolved with a junction table? Most problems show up in a quick pass over these three questions.

After unlocking, fix details directly in the Draw.io editor or describe the change in the AI panel. Because the output is a normal Draw.io file, you can also export it to PNG, PDF or SVG for a report, or keep it in your repository next to the schema.

An ER diagram models stored data. If you need to show behavior, such as the steps of a process, the messages between services, or the classes in your code, a UML diagram fits better. The UML diagram generator on this site covers class, use case, sequence, activity and state diagrams.

Many assignments ask for both: an ERD for the database and a class or use case diagram for the application. Generating both from the same description gives you a consistent starting point, and each opens in the same Draw.io editor.