Question

I’m still leanring PHP/MySQL but have learned quite a bit thanks to codies on StackOverflow. I’m trying to setup a sort of room reservations system using two tables:

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SETUP:

Room price table: Has, prices for a type room a client may want to rent as well as the dates (day of week) they wish to use it. Pricing varies based on day of the week and per room.

I’ve setup a different table for each room type as each room type carries different pricing for each day of the week. So, There is an Alpha room table, Bravo room, etc. Within Alpha table are headers for the days of the week with pricing pre-entered into the rows.

Client info table: Has the name, address, date of room use, etc data for the specific client.

EXAMPLE:

Alpha-room price table:
Sun = $100; Mon = $200; Tue=$300 and so on.

Bravo-room price table:
Sun = $100; Mon = $200; Tue=$300 and so on.

Client data table:
ClientName; date-of-room-use; address; day_subtotal; grand_total.

QUESTION:

I’m trying to find PHP code that will:

1. look at the date of room use in the client data table,
2. look up the associated cost for that date in the specific room pricing table,
3. record that unit cost in the day subtotal of the client data table
4. and sum a grand total in the grand total row of the client data
   table (assuming the room may be used more than one day by the
   customer).

I know there’s something to do with join but I’m finding it difficult to grasp the concept and, if someone can demonstrate using this example, I think I will have a better understanding of how to work this sort of transaction.

Thank you ALL in advance for your suggestions or alternatvie approaches.

Answer 1

First, you should separate your database slightly, you should have four tables. rooms, prices, clients and bookings. Setup somewhat like this…

rooms should have the following fields: id, name and description.

prices should have the following fields: id, price, room_id and day.

clients should have the following fields: id and whatever else you want to store on the user, such as first and last names, phone number or whatever.

bookings should have the following fields: id, client_id, room_id, started_at and ended_at. Preferably the started_at and ended_at fields will be an int, filled with PHP’s time() method.

You can add any extra fields you want/need to the tables.

With the tables separated out like this, you will be able to properly query the database. So to answer your questions…

1. look at the date of room in use…
   You can now query to see if a room is in use on a specific date by doing the following…

   <?php
   $selectedDate= mktime(); // Create a UNIX timestamp based on the day the user selected.
   $query = "SELECT r.name, r.description
             FROM rooms r, bookings b
             WHERE b.room_id = r.id
             AND b.started_at < $selectedDate
             OR b.ended_at > $selectedDate";
   $result = $pdo->query($query);
   ?>
   

2. Look up cost for that date

   <?php
   $selectedDate = mktime() // Create a UNIX timestamp based on the day the user selected
   $dayOfWeek = Date('N', $selectedDate); // This will give the numerical day of the week.
   $query = "SELECT price
             FROM prices
             WHERE room_id = $roomId
             AND day = $dayOfWeek";
   $result = $pdo->query($query);
   ?>
   

3. Record that unit cost in the client table

   Doing this is just silly on account of already having the information in another table. Never recreate the same information in a database. If you are, you have built your database incorrectly.

4. Grand total in the customer table

   Again, silly… don’t recreate data…

   1. Though, to find that information out, you would first need to do a query on the bookings table, and see the start and end date for which the user will be occupying the room.

   2. Do a calculation on how long the client will be in the room for, (ended_at – started_at) / 86400, (86400 is the number of seconds in a day) that will give the number of days the client is in the room for.

   3. Now that you know which days, and how long the client will be in the room, you can dynamically create a sql call to select the days of the week you need, remember Date('N', $timeStamp) will give you the numerical day of the week for a given timestamp.

   4. Then it is just a matter of doing simple addition.

I have given you the basics here, You can modify the query from answer one to show you if a room is available to be booked within the time frame the user asked for.

I hope that covers everything you asked about…