Question

I am relatively new to to database relationships, and I would love some advice on setting up my database for a basic registration for sessions.

GOAL:
Post a new session that people can sign up for. Maximum of 8 people per session. Admin side can see those who have signed up.

Here is what I currently have from a front end (the signup box at the bottom is just there temporarily as I work with this):

I have the backend working to create a new training session on POST:

<?php 

session_start();
include ('global/db/connection.php');
$session_name = $_POST['session_name'];
$session_description = $_POST['session_description'];
$session_date = $_POST['session_date'];

$result=MYSQL_QUERY("INSERT INTO trainingsessions (id,session_name,session_description,session_date,session_open_slots,session_booked_slots)".
   "VALUES ('NULL', '$session_name', '$session_description', '$session_date', '8', '0')");

header("location: admin.php");

?>

I also have been able to query the table and display the results in the table above. What I am trying to figure out is what sort of relationship and tables I need to create between the users and then displaying the appropriate amount of slots that are still open.

Very basic, nothing fancy at the moment. Just trying to get some fundamentals in with not luck thru other searches. Hope this makes sense, and thanks for your help!

Answer 1

You will have a many to many relationship between users and sessions (presumably). In essence each user could be assigned to many sessions, and each session will have multiple users. For that reason, you need an intersecting table that creates a composite key (the primary key is defined by multiple fields). For example, I would make the following tables:

Table: user
Columns: ID (primary key), Username, email

Table: sessions
 columns: ID (primary Key), Name, Description, Date

Table: user_sessions
columns: user_id, session_id

Using this structure, users can have multiple sessions and sessions can have multiple users.