DbNinja is a fresh, web-based MySQL database management applicationthat is built with PHP.

The application has a desktop-like, slick interface and can connect to multiple local + remote databases.

DbNinja allows working on multiple tasks at the same time with the ability to run each task on a different tab.

It is possible to create/edit/delete databases, tables, rows, procedures, triggers and much more.

There is syntax-highlighting support when creating queries (it is also possible to save them for future use) and a context-menu exists for browsing quickly.

Besides a specific database, we can also manage users, their privileges and edit values of system variables.

P.S. DbNinja is free for personal use.

Today, while many websites have a database for storing the content, settings, etc., many others are static and don't use anything to keep the data as they are hard-coded in HTML.

For such websites, we may still want/need to store several things and OpenKeyval provides us that opportunity without setting up a database like MySQL, MSSQL.

It is a free (also open source) and web-based database service that doesn't require any registration and can be used instantly.

We simply send a POST request to store any data (with a unique prefix of our preference), can request or delete it anytime and responses comes in a JSONformat.

Also, like mentioned, OpenKeyval is open source. It is built with PHP and anyone can host their own instance.

P.S. The only limitation of the service is the size of each key which is 64kb.