Updating membership MySQL database automatically in PHP - php

Question

I have set up the database with all the various fields and can carry out all the necessary registration and logins etc. – so far so good!
What I need to do now is as follows:
When a new member attempts to register he/she must provide the email address of an existing member (like a sponsor, as it were). If the sponsor email is a fake or doesn’t exist in the data base, the application to join is rejected.
If genuine, I need to automatically retrieve the record of the sponsor and update his/her record by putting the new member in one of two possible fields. Each member is allowed to sponsor two and only two new members. So if the sponsor has no new members, field-A and field-B will be empty, therefore the email of the new member will be allocated to field-A. If, on the other hand there is already an entry in field-A, the new member email will be stored in field-B. If both are already filled a warning will be flagged and the sponsor will be refused permission to introduce the “third” new member.
I would be most appreciative of any help with this, having spent the best part of a week researching without success. I am sure there is a fairly simple answer from an expert on this wonderful site.

Answer 1

Fang Man,
I would not use 2 columns for this.
I would create a new table member_sponsors for instance.
It would consist of:
id - auto incrementing primary index
sponser_id - id of sponsor
memeber_id - id of new memeber
sponsor_date - date member was sponsored?
This way you can simply query this table and check if it contains less then 2 (or if down the road you want to increase this value this can be done easily).
Then just add the info to this table.
Hope this concept makes sense and is helpful to you.
Tim

Answer 2

Assuming your table with the existing members is called "members" with the following structure:
Field name Type
------------------------------------------
id int (primary, auto)
name varchar
email varchar
submember1 int
submember2 int
When the registration request is submitted, I assume you'll have a value like "sponsor_email" to check. After sanitizing this value and ensuring that it is an email address (hint: use regex), grab the info about your member:
SELECT
id,
name,
submember1,
submember2
FROM
members
WHERE
email = "'.$sponsor_email.'"
... and make sure the user signing up has a valid member's email address. If so, check to see if that member has an open slot:
if ($member['submember1'] > 0 && $member['submember2'] > 0) {
// add warning to sponsor, reject the signup
}
Now, you'll have to figure out which slot to put this new signup in - if $member['submember1'] is greater than zero (already filled), the signup goes in slot 2, else slot 1.
A much more flexible way is to add an associative table linking members and the sponsors, do this instead of adding fields to track this in the member table. There are a few advantages to this approach, most importantly that if you decide you want to increase the limit 5 submembers instead of 2 (for example), you can easily change a few small spots in the code without touching the database structure. Done "your way", you would have to change the database AND the code...
if ($member['submember1'] > 0 && $member['submember2'] > 0 && $member['submember3'] > 0 && $member['submember4'] > 0 && $member['submember5'] >0) {
// add warning to sponsor, reject the signup
}
... yuck! Plus, this will get hairy deciding which slot to put the new signup in. An associative table does not have this problem. Using the associative table route, you still have the members table:
Field name Type
------------------------------------------
id int (primary, auto)
name varchar
email varchar
... and then you have a member_sponsors table:
Field name Type
------------------------------------------
id int (primary, auto)
sponsor_id int
member_id int
The member_id field holds the id of the "sponsoring" member, the sponsor_id field holds the id of the "sponsored" member.
Using these tables in the signup process, again, get your member, but also do a join and count of their current sponsors
SELECT
members.id,
members.name,
COUNT(member_sponsors.id) AS sponsored_count
FROM
members
LEFT JOIN
member_sponsors ON
member_sponsors.member_id = members.id
WHERE
email = "'.$sponsor_email.'"
GROUP BY
members.id
Now, as long as the email matches, you will have a row with the id, name, and current number of sponsored members the given user has. Your php would now look like this:
$limit_on_sponsorships = 2;
if ($member['sponsored_count'] >= $limit_on_sponsorships) {
// add warning to sponsor, reject the signup
}
$limit_on_sponsorships can come from anywhere, make it a constant, make it a database setting, etc... all you have to do now to make a change to the number of allowed sponsors is modify that one value. Using this method makes your code more flexible and ready for changes.