Coming up with a business logic helper class

[eluser]afro[/eluser]
Am using mysql database, i have a table called staff, where i save the date of application for leave
, the date to start the leave and also the date the staff is expected to come back, reporting date
so the function should be able to check those who have have applied for a leave, if they are are more than
3 the system should then check the table of those on leave grouping by the department and select the staff
who first went for the leave and tell the applicant that he/she will be able to apply for leave after the first person form the
department comes back.the table that hold the record for those on leave is called staff_on_leave.

hope that will be satisfactory.