License introduction

ShardingSphere uses the Apache Software Foundation's license. The Foundation offers multiple licenses to distribute both software and documentation, while our community uses what is known as the Apache License 2.0.

This license was approved by the Foundation in 2004 and is part of what is known as permissive licenses, as opposed to copyleft licenses.

Copyleft licenses are so called because they require any code that is built as derivative work of the copyleft licensed software to be released under the same license as the original software.

On the other hand, permissive licenses, such as the Apache License 2.0, do not have any such requirement. This means that as a user using software such as ShardingSphere, you can do nearly anything with the code. Examples include sublicensing the code, including it in a commercial product you're building, distributing any copies or modifications of the code, or simply altering the code.

For a complete...