Hi Raed,
MobiOne apps have access to the HTML5 local storage and web db facilities. Thus you can access web db via the javascript sql api. There are many tutorials online that demonstrate various approaches to database use.
But you should ensure that you absolutely need a relational db for your app before commiting to such as service. For example in many cases the HTML5 local storage is faster and simpler to deal with. Also web db is not a standard and is no longer supported by the w3c.
If you run the Test Center emulator, there is a Notes example that is built on web db. You can download the source code here: http://genuitec.com/mobile/mobione/dev/web/sticky-notes.zip