Recently I was looking for a data modeling tool. I’ve written about how I use the DBeaver query tool, and it supports creating database diagrams from existing tables, but I wanted to see what was available for tools to create the data model. There are plenty of good enterprise level tools, but they can costs hundreds into the thousands of dollars. I’m sure those tools are worth it, but I was just looking to create simple models. I wanted to be able to create a Logical design, then covert it to a Physical design later. It would be helpful if it also could work with existing databases and create diagrams for existing models.
I ran across these four programs/services. I was already familiar with Vertabelo, but I didn’t know about the others. DB Diagram was interesting, how it used DBML code to define the data structures. Any prices listed are as of June 2022.

Also, Syncfusion has posted a book named Database Design Succinctly. I think it’s a good introduction to the basics of design, for any beginners looking to become more familiar with this area.

Desktop app
Logical and Physical design
Export to PDF, HTML, Image files
Supports all major relational DBs
Mongo DB support – reverse engineer collection
Connect to DB to import model
Sync changes to DB
Free version – Personal license $196

DB Designer
Logical design
Export to PDF, Image, SQL Script
Import SQL – Not script, paste in SQL
Supports MySQL, MS SQL, PostgreSQL, Oracle and SQLite
Public sharing of model
Free version – Basic $7 mo, Unlimited $16 mo

DB Diagram
Uses DBML code to construct model
Works with MySql, Postgres, SQL Server
Import and Export SQL scripts
Export to PNG and PDF
Free version – $9 mo for Unlimited, collaboration, versioning

Physical model – Logical with Team or Enterprise
Export to PDF or PNG, XML
Supports all major relational DBs
Import model – Export to SQL script
Personal $29 mo – No free plan – Team and Enterprise plans

ERD Notations – Links:

Vertabelo – ERD Notations

Gleek – ER Symbols and Notation

UPDATED – Mar 2023:
Posted on the ERD Lab Data Modeling Tool