AngularJS + Ionic: Checking if new Entry in Database, if yes: Push notification

Hi, I am working on an application with ionic and angularjs. I would like, that the app checks automatically in the background, if new database entries are available. If yes, it should send a notification. My question: How can I check in the background continiously, if there is an database update?
And Question #2: If there is no entry in the database, it should throw you out of the actual page.

Background: I am working on an live-survey app for events, with which you can interact with the show on the stage. If a question is activated for the people, you should get a notification.