Tag Cloud for PHP + MySQL

Just inspired by the topic - habrahabr.ru/blog/php/48543.html#habracut

Everything is easy to impossible. This is an example of displaying a tag cloud for photos. The code is not perfect, the algorithm is also simple. But the result is pretty kosher.

Tags are stored in the table in the form - id | text
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CREATE TABLE `users_tags` (
`id` int(11) unsigned NOT NULL auto_increment,
`text` varchar(255) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `txt` (`text`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

And this is a link table.

CREATE TABLE `users_fun_photos_tags_data` (
`photo_id` int(11) unsigned NOT NULL,
`tag_id` int(11) unsigned default NULL,
KEY `tag_id` (`tag_id`),
KEY `photo_id` (`photo_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;


This is the table where the photos themselves sit.

CREATE TABLE `users_fun_photos` (
`id` int(11) unsigned NOT NULL auto_increment,
`title` varchar(255) default NULL,
`tags` varchar(255) default NULL, /* , */
`cat_id` int(11) unsigned NOT NULL default '1',
`file` varchar(30) default NULL,
`dir` varchar(3) default NULL,
`user_id` int(11) unsigned default '1',
`date` datetime NOT NULL default '0000-00-00 00:00:00',
`date_last_comment` datetime default NULL,
`comments` int(11) unsigned NOT NULL default '0',
`views` int(11) NOT NULL default '0',
`points` int(11) default '0',
PRIMARY KEY (`id`),
KEY `views` (`views`),
KEY `user_id` (`user_id`),
KEY `comments` (`comments`),
KEY `cat_id` (`cat_id`),
KEY `title` (`title`),
KEY `tags` (`tags`),
KEY `date` (`date`),
KEY `date_last_comment` (`date_last_comment`),
KEY `points` (`points`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

Well, here is the actual function that displays the cloud itself.

function GetAllTagsFromDB ()
{
# This is mine, you may be different
global $ prefix, $ dbi;

$ data = NULL; # There will be output
$ list_tags = array (); # There will be text tags
$ list_ids = array (); # Id tags here

# Specifying maximum and minimum font size
$ max_size = 300; # Maximum font size in percent
$ min_size = 100; #Minimum font size, also in percent

# Select data where quantity - how many times a tag occurs, tag_text - text and tag_id - tag id, respectively
$ res = sql_query ( "SELECT COUNT (a.photo_id) AS quantity, b.text, b.id from„ . $ prefix. "_users_fun_photos_tags_data a," . $ prefix. "_users_tags b where a.tag_id = b.id group by a.tag_id " , $ dbi);
while (list ($ quantity, $ tag_text, $ tag_id) = sql_fetch_row ($ res))
{
$ list_ids [$ tag_id] = $ quantity; # Add id tags to the array
$ list_tags [$ tag_id] = $ tag_text; # Add tag text to array
# Note that the key of the array is the id of the tag
}

# Sort the tag array
asort ($ list_tags);

# Check if array is not empty
if (! empty ($ list_tags))
{
# Choose the maximum and minimum quantity
$ max_qty = max (array_values ​​($ list_ids));
$ min_qty = min (array_values ​​($ list_ids));

# Calculate the difference between the maximum and minimum quantity
$ difference = $ max_qty - $ min_qty;
# It is impossible to divide by zero
if (0 == $ difference)
{
$ difference = 1;
}
# Calculate increment of font size
$ step = ($ max_size - $ min_size) / ($ difference);

# Go through the array of tags
foreach ($ list_tags as $ key => $ value )
{
# Calculate future font size
$ size = ceil ($ min_size + (($ list_ids [$ key] - $ min_qty) * $ step));

$ data. = '<a style = "font-size:' . $ size. '% "Href =" index.php? Section = Fun & file = search & tag_id =' . $ Key. ''> ' . $ List_tags [$ key]. '</a>' ;

}
}
return $ data;
} * This source code was highlighted with Source Code Highlighter .