Hello, 
I need to develop a trigger on this. Can anyone help me with that?

Develop a Trigger on Service-Consultant object which will throw an error if the Consultant Selected on
Service-Consultant Record already has an Service against his name. i.e - For a Consultant there will be only one Service at a time. Reject Duplicate Bookings.
Q1 - In which object the Trigger will be ( Service-Consultant) Q2 - What are the trigger events ( before insert, before update) Output - Check the duplicate bookings and throw the error.