JayData is cross-platform (runs on HTML5 desktop and mobile browsers, can be hosted in PhoneGap environment on iPhone, iPad and Android) and cross-layer as it works on client-side and server-side (Node.JS).
WebSQL SQLite HTML5 localStorage IndexedDB OData MongoDB Facebook YQL
Please read the release notes for current status of the providers.
Visit http://jaydata.org for detailed information and documentation.
As JayData covers many technologies and open new fields of development, we encourage you to contribute to the project with new providers or features. Check out the possible ways of contributions here: http://jaydata.org/community/contribute
JayData comes with dual licensing: you can use it under MIT license if ship software software under MIT, but it should be used under GPL if you distribute your software under GPLv2.