What you can do is:
Make sure you have a start date and end date attribute for the appointment entity.
request all appointments that belong to that particular doctor on that specific date/time frame.
If empty there are no appointments for that time so it is safe to book.
If this is unclear or not the answer you are looking for, please let me know
were do I use this microflow can you give me an example.
I believe the domain model should look like this
When the employee makes a doctor’s appointment, he selects the doctor, the customer and the date, begin time, end time.
With a microflow we can check if this doctor has already an appointment for the same date within the period selected , if so we can inform with a message (and don’t commit the object schedule).
In the retrieve activity should have a Xpath constraint:
[Notifications.Schedule_Doctor = $Doctor]
and similar to this:
I hope that helps,
please let me know if you achieve and the solution :)
Depends on what exactly you want, what your page looks like etc.
From what I can see now is that the microflow has to get its parameters filled first. So on the page there must be a object that gives you those fields.