explode() and arrays

[tleisher]

Alright, so here's how my database works. If someone adds a book as their favorite it takes their current favorite book column, adds "," and then the book name so it comes up  like "1,2,3".

Then in the favbook.php file, I want to have it display all the usernames of the people who have the book id in their fav_book column.

So far I figured that I should read that column with a mysql query, then mysql_fetch_array the query, and then explode(",", $fav_book);

But how would I do this in a loop so that it reads through the array and if it doesnt find $_GET["id"] then it doesn't print that username, then continues on to the next row with the new username and so on until it gets to the bottom of the table?

[.josh]

[code]
foreach ($fav_book as $val) {
  if $(_GET['id'] == $val) {
      // print username or whatever
  }
}
[/code]

[Jenk]

Just a note.. this method of storage (delimeted list) is looked upon as 'sloppy' because, well, it is sloppy.

Use a table to store all the users entries with a foreign key for the user id and a foreign key for the book details. Essentiall 3 columns: index, userid, bookid.

Then select the rows from that table, with joins on users and books if necessary. It will be MUCH more efficient.

[.josh]

in other words, read up on relational databases.

[tleisher]

So have a completely different table for favorites?

Like:

Userid - Book ID
1            2
1            5
3            2

and so on?

[Jenk]

yes, with it's own index field:

[code]CREATE TABLE `favorites`(
    `id` INT NOT NULL AUTO_INCREMENT,
    `bookid` INT NOT NULL,
    `userid` INT NOT NULL
) PRIMARY KEY(`id`);[/code]