Create Polygon on Google Map By dragging mouse

I am first time using Google Map..

I have to add the Google Map in my web application with following functionality.

1. User can create polygon on the Map by using Mouse.
2. Then the values of polygon's Lat/Lon will be saved in the Database.开发者_开发问答
3. Like wise he can create multiple polygons but with the restriction that any polygons should not be overlapped.

Please help me on it.. Thaks in advance

As far as rendering the polys I would consider using a open source tool kit that already does that . Open Layers is a nice javascript library that works with Google Maps enables you to draw overlays and collect lat lon information, etc. As far as the database entries and overlapping issues see the comments on your question.