category.php
<?php
class Category extends AppModel {
	var $name = 'Category';
	var $hasAndBelongsToMany = array('Category' =>
				array(	'className'	=> 'Category',
					'joinTable'	=> 'categories_categories',
					'foreignKey'	=> 'category_id',
					'associationForeignKey' => 'child_id',
					'order' => 'Category.name ASC'
				),

			       );
	var $recursive = 1000;
}
?>

work.php
<?php
class Work extends AppModel {
	var $name = 'Work';
	var $belongsTo = array('User');

	var $hasAndBelongsToMany = array(
				'Category' =>
				array(	'className'	=> 'Category',
					'joinTable'	=> 'works_categories',
					'foreignKey'	=> 'work_id',
					'associationForeignKey' => 'category_id',
					'conditions'	=> '',
				),
			       );
	/*
	var $hasAndBelongsToMany = array('Category' =>
				array(	'className'	=> 'Category',
					'joinTable'	=> 'works_categories',
				),
			       );
	*/
}
?>

works_category.php
<?php
class Works_category extends AppModel {
	var $name = 'Works_category';
	var $useTable = 'works_categories';
	var $belongsTo = array('Work', 'Category');
}
?>