Question: In a scenario like below 

![scenario](https://i.stack.imgur.com/SX8Ig.jpg)

assignee and assigner are keys of developer and tester. how to map the emp\_id as a foreign key without getting duplicated?

Answer: 
start a service and your alarm code in that.Once the alarm is done start your application through notification or as per your logic.
You should use Service, Open your activity through service. [Service](http://developer.android.com/guide/components/services.html)