Database Manager - DBGate

 If you are looking for a web-based database manager that is open-source and commercial friendly, then please have a look at DBGate: https://github.com/dbgate/dbgate

Since it is web-based, you can see a good demo here: https://demo.dbgate.org/

Cool open source tool for ER diagrams

Recently one of my colleagues introduced me to a cool Java tool called SchemaSpy.
SchemaSpy is a java tool that can be used to create beautiful database documentation and also ER diagrams.

Would highly recommend perusing the following links and utilizing this tool:

• GUI for SchemaSpy:  http://schemaspygui.sourceforge.net/
• Documentation:  http://schemaspy.readthedocs.io/en/latest/
• Source Code: https://github.com/schemaspy/schemaspy

Free Data Modeling tools

There are a plethora of free and opensource UML modeling tools available in the market. But there is very little awareness regarding free database modeling tools. Jotting down a few free tools that are very good for ER modeling and support most popular databases for script generation.

1. Oracle SQL Developer Data Modeler: This cool modeling tool from Oracle is actually free! It supports physical model creation for SQL Server, IBM DB2 and ofcourse Oracle DBs.
2. DBDesigner: In the past, I have used this extensively when working with MySQL databases.
3. MySQL Workbench: Another good tool if you are using MySQL.
4. Aris Express: Software AG's popular Enterprise Architecture tool ARIS now comes with a express (community) edition that can be used for business process modeling and ER modeling.