php - laravel : How to handle time overlapping in database? - php

Question

I want to save two time interval in my database. where it will check the database and if someone already booked that time it won't save the time whereas if it's empty it will save time which user will give as a input.
Eg. A user want to book the schedule 8:00 to 8:30, while saving into
the database it will check in the database whether someone already take
that time or not, if it's not then it will save otherwise it won't. Meanwhile
user can't give input even in 8:15 also.
How do i solve this overlapping problem?
here is the controller code I have used, it doesn't running though:
public function postAllocateRoom(Request $request)
{
$classRoom = new ClassRoom();
$classRoom->department_id=$request->Input(['department_id']);
$classRoom->room_id=$request->Input(['room_id']);
$classRoom->course_id=$request->Input(['course_id']);
$classRoom->day_id=$request->Input(['day_id']);
$classRoom->start=$request->Input(['start']);
$classRoom->end=$request->Input(['end']);
$startTime = Carbon::parse($request->input('start'));
$endTime = Carbon::parse($request->input('end'));
$classRoomCount = ClassRoom::where(function ($query) {
$query->where('start', '>=', $startTime)
->where('end', '<=', $startTime); })->count();
$messages ="Class Room Already Taken";
if ($classRoomCount > 0) {
return redirect('allocateRoomPage',$message);
}
else {
$classRoom->save();
return redirect('allocateRoomPage');
}
}

Answer 1

The rule for time overlapping is simple (see here for a complete graphic explanation):
start1 < end2 AND end1 > start2
So your query can be:
$classRoomCount = ClassRoom::where
(
function( $query ) use( $startTime, $endTime )
{
$query->where( 'start', '<', $endTime )
->where( 'end', '>', $startTime);
}
)->count();

Answer 2

Firstly, to be able to have access to $startTime and $endTime within the query closure you will need to pass them through using the use construct i.e.
function ($query) use ($startTime, $endTime)
The following should work to get the correct counts for classrooms booked between certain times:
$classRoomCount = ClassRoom::where(function ($query) use ($startTime, $endTime) {
$query
->where(function ($query) use ($startTime, $endTime) {
$query
->where('start', '>=', $startTime)
->where('end', '<', $startTime);
})
->orWhere(function ($query) use ($startTime, $endTime) {
$query
->where('start', '<', $endTime)
->where('end', '>=', $endTime);
});
})->count();
Hope this helps!