The purpose of an Entity Relationship Diagram (ERD) is to plan out the relationships between entities in your data model. An ERD uses special symbols to demonstrate a kind of relationship between two entities: one-to-many, many-to-many, one-to-one. It can even get more specialized in showing the number of required records in a table (0 or more, 1 or more, 1 only, etc).
The ERD might end up resembling a spider web, a confusing-seeming diagram of boxes and lines, but after studying the diagram, one can clearly see the relationships.
Here are some tools that people have used to create an ERD:
|Free ER Diagram Tool||Web|
|FileMaker||macOS and Windows||FM Buttons and Lines|
|OmniGraffle||macOS||AppleScript'able and good for lots of things|
|Yed||Mac, Win, Linux, Java, Web||https://www.yworks.com/products/yed|
|Inspiration||Mac, Win, iOS|
Inspiration Software, Inc. - The Leader in Visual Thinking and Learning | inspiration.com Fairly simple. Originally designed for teachers and students. Works well. Much less bloat than OmniGraffle or other such tools. Simple. Fast. Can instantly switch between outline and diagram view, and export outlines with notes attached as a Word/Text doc.
|Gliffy||Web, Chrome extension||Gliffy Online Extras|
|Pen and Paper / Whiteboard||N/A|
When I architect an ERD I will typically do it on a piece of paper and / or a whiteboard.
When I need to document an ERD I typically use Gliffy
|MySQL Workbench||Mac, Win, Linux|
Can create ER Models ( and of course able to connect to MySQL database and edit data / schema)
|Microsoft Visio||Windows (maybe iOS too?)||Has many built in useful drawing types. Uses a Microsoft proprietary file format that created extraordinarily large files from what you would expect.|
|Sparx Systems Enterprise Architect||Windows||Full blown database engineering management system for SQL but has lots of functionality that can be used for FM.|
|CMAPtools||Mac, Win, iPad, Linux, Cloud, Server|
Concept mapping, a superset of mind-mapping, is used for depicting relationship concepts. This is a free tool, a result of research conducted at the Florida Institute for Human & Machine Cognition (IHMC). It empowers users to construct, navigate, share and criticize knowledge models represented as concept maps.
|dBeaver||Mac/Win/Linux||DBeaver Community | Free Universal Database Tool|
Includes the automatic diagram transition from IDEF1x (Data) and IDEF0 (Process) diagrams from a single source input.