How to implement JAX-WS with SQL database

I am trying to develop a web service which will later on be consumed to build a

• front-end application for teachers to update student progress.
• Android App for parents to view these updates.

Keeping in mind that there will be many teachers teaching many students is using a Web Service such as JAX-WS the best idea to implement something like this? Or should I be going in a different direction.

Also how should I be using databases to store all the data?

I am pretty new to the programming world so please excuse any stupid questions which I may ask.