Validate if the selected date and time is free to choose.
The user selects a date and a time (datetime) in a form field.
The user will then receive a message if this time is available or occupied. If it is busy, an error will occur.
The idea is that when a user has filled in a start time and an end time, this time cannot be used by anyone else.
I imagine that the database table should contain a start time (datetime) and an end time. And I am now wondering if there is any way to validate this.