When working with JSON strings, it is usually hard too understand their hierarchy at the first look.
JSONmate is a web app that can beautify (and uglify) JSON strings where these strings can be directly pasted or loaded from a remote URL.
Also, it has a very nice visual editor for customizing the data and a visualizer that provides a different view for it.
JSONmate has support for JSONP too and it is an open source project.
Sometimes, we don’t know how our SQL query will look like exactly as there are times that the query needs to be created dynamically.
Or, you may just be looking for a solution that will make SQL queries more readable.
It works both on the browser (not advised as the queries will be visible to all) + with nodejs and supports all standard SQL queries (can be customized to support non-standard queries).
Medoo is a lightweight (~8kb) PHP framework for working with SQL databases.
The framework comes as a single file and works with MySQL, MSSQL, PostgreSQL, SQLite (and more).
It has methods for all the common SQL queries and controls for preventing SQL injention.
Medoo is simple-yet-handy and it is very well-documented.
Requirements: PHP 5.1+
Induction is an open source and free tool for understanding and communicating relationships in data.
It can be used to explore rows/columns, run queries and visualize the data in several ways.
The tool has support for many databases including PostgreSQL, MySQL, SQLite, Redis and MongoDB. Also, any others can be added by writing new adapters.
Induction is currently in alpha and not a full-featured client yet but has a roadmap to become one.
Requirements: Mac OS X
For NoSQL fans, MongoDB is definitely the most popular solution with the simplicity and cross-platform support offered.
In order to manage MongoDB databases easily, Genghis, a single-file, self-hosted and web-based solution is pretty handy.
It can be installed either as a Ruby gem or as a standalone PHP script.
Genghis is capable of managing any number of databases on any number of servers with support for managing databases, collections and documents.
The interface of the application is responsive and works well down to mobile.
Requirements: PHP or Ruby on Rails
Git, Subversion and other version control systems are great for managing projects within a team and making sure that everyone in the team gets the latest versions of each file.
However, versioning databases is not a built-in feature in such systems and they should definitely be synchronized too.
DBV is an open source and PHP-powered application that can help us include databases in to the version control system we are using.
Once installed, it tracks each schema/record change (tables, rows, columns, views, functions, etc.) and allows us to export a SQL file reflecting the change (to a folder we want).
As this SQL file will also be committed with th version control system we are using, it’ll be received with other team members.
DBV supports MySQL by default and has a simple interface to implement connectors for any other databases.
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 JSON format.
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.
Requirements: No Requirements
DbNinja is a fresh, web-based MySQL database management application that 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.
Requirements: PHP 5.3+
For anyone working with multiple database engines, regularly switching between different apps to manage them can be a pain.
DBeaver is a free database management application which works with many different engines including MySQL, MSSQL, Oracle, SQLite, Sybase, Firebird and much more.
As the application is built with Java, it works in all major operating systems (Windows, Mac & Linux).
It can handle all the major tasks like metadata editing (tables, columns, keys, indexes), custom SQL execution, users management, multiple connections, etc.
We can draw ER diagrams for database modeling, and, the app is soon to be open sourced.
Requirements: Java 1.6+
For MySQL users, phpMyAdmin -the popular MySQL admin tool-, is probably one of the most-used apps unless you are fan of a desktop MySQL admin tool.
MyWebSQL is an exciting open source alternative to both as it is a web-based MySQL (and SQLite) manager with a desktop-like functionality.
It is built with PHP and, with the help of a completely Ajaxed interface, tasks can be accomplished pretty quickly.
Creating, editing and deleting tables or records are easily done in a grid mode which also makes working with multiple items at the same time possible. Also, shortcuts for any actions exist inside context menus to make browsing faster.
There are other must-have features like import-export, SQL editor (with syntax highlighting), repair tables, search, process manager, etc.
MyWebSQL is a multilanguage app with lots of ready-to-use languages and has a themable interface.
Imho, what is missing the most is the ability to manage multiple server connections with a single login and scheduled tasks (which I hope would exist in the future versions).
Compatibility: All Major Browsers