First and foremost - thanks for any help offered (I'm a newbie to PostgreSQL and PHP but proficient in SQL and .NET)!
My question: Most appropriate way (and how) to conditionally test for records existence and then insert or update and delete.
The App: a calendar reservation system. Imagine a table 7 columns wide and 24 rows deep (7 days, 24 hours). User clicks a cell to reserve time.
For speed, I want as much processing performed within the server so for the table cell's onclick event i would call up to PostgreSQL passing user's ID, date, hour. The function/procedure/trigger (which do i use?) would accept the parameters and 1) see if that time slot is taken, if not, then check to see if this user has reserved time slot on either side of this one, Yes - modify that record to expand it's time frame, No - Insert record to signify this user reserved this time slot. If the time slot was taken then check to see if taken by this user, Yes - then remove the time slot reservation, No - nothing, return message or code for you cannot add/remove another users reservation.
Reservations
pk serial
users_id int
time_begin timestamp
time_end timestamp
My question: Most appropriate way (and how) to conditionally test for records existence and then insert or update and delete.
The App: a calendar reservation system. Imagine a table 7 columns wide and 24 rows deep (7 days, 24 hours). User clicks a cell to reserve time.
For speed, I want as much processing performed within the server so for the table cell's onclick event i would call up to PostgreSQL passing user's ID, date, hour. The function/procedure/trigger (which do i use?) would accept the parameters and 1) see if that time slot is taken, if not, then check to see if this user has reserved time slot on either side of this one, Yes - modify that record to expand it's time frame, No - Insert record to signify this user reserved this time slot. If the time slot was taken then check to see if taken by this user, Yes - then remove the time slot reservation, No - nothing, return message or code for you cannot add/remove another users reservation.
Reservations
pk serial
users_id int
time_begin timestamp
time_end timestamp