Question

The system is as such. Tutors provide their availability (Monday – Sunday) and the time frame they are available on that day (0700 – 1400) (ie: 7am – 2pm).

I am trying to figure out the best way to store and search through this information to find available tutors. Searching only needs to be done on a daily system (ie: day of the week – mon, tues, wed, etc).

My planned infrastructure:

//Tutor Availability
---------------------------------------------------------------------------
  tutorID  |  monday   |  tuesday  | wednesday  | thursday   |   friday   |
---------------------------------------------------------------------------
   27      | 0700-1200 |   NULL    | 1400-1800  |  NULL      |    NULL    |
---------------------------------------------------------------------------
   35      |   NULL    | 1400-1600 |    NULL    |  NULL      | 1100-1900  |

//Scheduled tutor sessions
------------------------------------
  tutorID  |    day    |  time     | 
------------------------------------
   27      |  monday   | 0700-0900 | 
------------------------------------
   35      |  friday   | 1300-1500 |

Query: SELECT tutorid FROM tutoravailability WHERE 'monday'=… is available between 0900-1100 and is not in scheduled tutor session.

I have been searching forever about how I can search through (and store) these time intervals in MySQL. Is this the best way to store the time intervals of a 24 hours day? Will it even be possible to search between these intervals? Am I approaching this from the wrong way? Any insight is appreciated.

Updated Infrastructure

//Tutor Availability
-----------------------------------------------------
  tutorID  |  day   | start_time | end_time  |  PK  | 
-----------------------------------------------------
   27      |  mon   |   0700     |   1200    |  1   |
-----------------------------------------------------
   27      |  fri   |   1400     |   1800    |  2   |
-----------------------------------------------------
   35      |  tue   |   1100     |   1600    |  3   |
//Scheduled tutor sessions
--------------------------------------------------------
  tutorID  |    day    |  start_time | end_time  |  PK |
--------------------------------------------------------
   27      |    mon    |     0800    | 1000      |  1  |
--------------------------------------------------------
   27      |    fri    |     1600    | 1800      |  2  |

So with this system it will be much simpler to search for available times. However I am still at a loss as to how to compare the availability against the scheduled lessons to ensure no overlap.

SELECT tutorID 
FROM tutoravailability WHERE day = 'fri' 
AND start_time <= '1400' 
AND end_time >= '1530'

Now I don’t understand how I would compare this query against the Scheduled tutor sessions table to avoid duplicate bookings.

Final Update

To ensure their are no overlapping of the Scheduled Tutors sessions I will use the MySQL BETWEEN clause to search for the start and end time.

Answer 1

If you store the time interval using two columns it will be much easier for you to perform a search using sql query.

i.e. tutorID, day, startTime, endTime