What is the semester which most student registered in? Show both the name and the id.
SELECT T1.semester_name ,  T1.semester_id FROM Semesters AS T1 JOIN Student_Enrolment AS T2 ON T1.semester_id  =  T2.semester_id GROUP BY T1.semester_id ORDER BY count(*) DESC LIMIT 1
SELECT T1.semester_name ,  T1.semester_id FROM Semesters AS T1 JOIN Student_Enrolment AS T2 ON T1.semester_id  =  T2.semester_id GROUP BY T1.semester_id ORDER BY count(*) DESC LIMIT 1
[{'semester_name': 'summer 2010', 'semester_id': 2}]