Create Layer editing/Analysis in an ArcGIS web map application using Javascript API

I want to make an ArcGIS web map application in which user can select different layers of the published map (data of the layer in Postrgresql) and do some analysis based on layer data.import data to the application. Some kind of Interactive map.

1) Do I need Geodatabase or just registered postgresql database with Arcgis for Server and ArcGIs for Desktop 10.1 is enough?

2) any sample template for javascript API is available?

Thank you