title: What is the best way to optimize schema for capturing attendance data
body: <p>We have a sports training camp which is regularly attended by various teams in the city. We have a session per day spanning 2 hrs(9-11 AM) and the time slots could vary for different teams. We would like to capture who attended the training camp on a daily basis.</p>
  
  <p>We arrived at the following model to capture attendance.
  (id, user_id, date, present). Assuming the user attends camp daily (say 30 days in a month), you will see that many records in the database.</p>
  
  <p>Assuming we are interested only in finding out the number of days the user has attended the camp, is there a better way to mark presence or absence of a particular user (maybe just have a single row for a month and mark all the individual days as something like (P,P,P,A, ...,A,P). P = Present, A = Absent</p>