How to map a reference selector(drop down) value to the database entity in Form ?

I have a drop down (Course Title) using reference selector field which is taking value from another database entity Course. I want to save this value in Registration table, but I am not able to find how to retrieve this value and map it to my registration entity Please advise.
2 answers

HI Abhishek Jain,
Can you show me the Screen shots of thepages and domain model ?



Please find the domain model.

There are 2 Entity  

- Course – Contain the Course Details

- Trainee – Contain  the Trainee(Student Details)

The final entity is Registration Entity

It has screen to select CourseTitle which is displayed from Course Entity

Trainee Name is displayed from Trainee Entity