One Article multiple categories system in PHP SQL - php

Question

Multiple categories selection system for Article
Earlier M using two tables
articles & categories and save category ID in articles table
But in this system I can save only one category ID per article
I want to save Article in Multiple categories
While searching I found same question on StackOverflow
I understand the whole concept of adding one more table of relationship & saving Article ID & Category ID in this table.
But not aware how to implement multiple selection system using arrays in New Article Form & Edit Article Form.
earlier I am showing Select in my form to display categories list in Add Article & Edit Article Page.
pls someone explain me How to show categories list in multiple checkbox style in my form so user can select multiple categories and then after POST how to get checkbox data and run query to insert data in both Article Table & New Relationship table with selected categories ID
want to display category List like this screenshot
Many Many Thanks...
EDIT:
I use echo '<input type="checkbox" name="selcats[]" value="$catid"> ' .$catname;
to display Categories check box
Its showing in a row side by side.
how to change display like screenshot i.e. list with scrollbar
& need to process this array and insert in new table while inserting article in databse.
EDIT 2
got the checkbox display correct in a scroll list by using a div :D
<div style="height: 150px; width: 200px; overflow: auto;">

Answer 1

In my case, I use a "tag system", for instance: You have an article with one category, nothing will change that... In adition, you can create another field in the article table with the relevant words (or whatever you want) and separete them with spaces or commas.
// Get the data from your database
$tags = 'world, travel, turism, cities';
// Separate the values
$tags = explode(", ", $tags);
// Create a link for each one
foreach($tags as $t)
{
echo ' ' . ucfirst($t) . ' ' . "\r\n";
}
It should output:
World
Travel
Turism
Cities
And it means that you can SELECT articles that have the title LIKE the tag, or whatever you want to search.
Is that what you was looking for?

Answer 2

You basically require two tables, with this structure
table_categories
_____________________________
| id | title |
-----------+---------------+
table_category_detail
______________________________________________
| id | categoryId | articleId |
-----------+---------------+------------------
To extract all categories, select all from the table_categories and put up into the select menu with mutiple selection enabled.
Next, when posted get the selected box values and insert into table_category_detail one by one
This is how you create a select box
$query = "SELECT * FROM table_categories";
$result = mysql_query($query);
echo '<select multiple="multiple">';
while($row = mysql_fetch_assoc($result)) {
echo '<option value="'.$row['id'].'">'.$row['title'].'</option>';
}
echo "</select>";
Or a Multiple Check Box
while($row = mysql_fetch_assoc($result)) {
echo '<input type="checkbox" name="selcats[]" value="'.$row['id'].'"> ' .$row['title'];
}
After the post:
// Here write codes to insert the article first
$articleId = mysql_insert_id(); //get the id
$values = $_POST['selcats'];
foreach($values as $value) {
$query = "INSERT into `table_category_detail` VALUES(NULL, $value, $articleId)";
$result = mysql_query($result);
}