Adds some NoSQL flavour to RDBMS's that Cake supports

optionable.php

<?php

/**
 * Adds some NoSQL flavour to any RDBMS that Cake supports
 *
 * Need to create a new table with the following schema...
 *
 * CREATE TABLE IF NOT EXISTS `options` (
 *   `id` int(11) NOT NULL auto_increment,
 *   `model` varchar(32) NOT NULL,
 *   `related_id` int(11) NOT NULL,
 *   `opt_key` varchar(32) NOT NULL,
 *   `opt_value` text NOT NULL,
 *   PRIMARY KEY (`id`),
 *   KEY `opt_key` (`opt_key`)
 * );
 */

class OptionableBehavior extends ModelBehavior {

    private $_settings = array();
    private $_toSave = array();
    private $_toFetch = array();
    private $_toDelete = array();

    public function setup(&$model, $settings = array()) {
        $this->_settings[$model->alias] = array();

        $defaults = array(
            'model' => 'Option',
            'fields' => array(),
            'emptyFields' => true
        );

        $this->_settings[$model->alias] = $settings + $defaults;

        $this->Model = ClassRegistry::init($this->_settings[$model->alias]['model']);
    }

    public function beforeFind(&$model, $query) {
        $fetch = true;
        $fields = $this->_settings[$model->alias]['fields'];

        if (isset($query['options']) && $query['options'] == false) {
            $fetch = false;
        }

        if ($fetch) {
            if (isset($query['fields'])) {
                foreach($fields as $field) {
                    if (in_array($field, (array) $query['fields'])) {
                        $this->_toFetch[] = $field;
                    } elseif (in_array($model->alias . '.' . $field, (array) $query['fields'])) {
                        $this->_toFetch[] = $field;
                    }
                }

                if (in_array('*', (array) $query['fields'])) {
                    $this->_toFetch += (array) $fields;
                } elseif (in_array($model->alias . '.*', (array) $query['fields'])) {
                    $this->_toFetch += (array) $fields;
                }

                $this->_toFetch = array_unique($this->_toFetch);

                if ($this->_toFetch) {
                    foreach ($query['fields'] as $k => $field) {
                        $field = (strpos($field, '.') === false)
                            ? $field
                            : str_replace($model->alias . '.', '', $field);

                        if (in_array($field, $this->_toFetch)) {
                            unset($query['fields'][$k]);
                        }
                    }
                }

                if (!in_array('id', (array) $query['fields'])
                    || !in_array($model->alias . '.id', (array) $query['fields'])) {
                    if (!is_array($query['fields'])) {
                        $query['fields'] = (array) $query['fields'];
                    }

                    $query['fields'][] = $model->alias . '.id';
                }
            } else {
                $this->_toFetch = (array) $fields;
            }
        }

        return $query;
    }

    public function afterFind(&$model, $results, $primary) {
        if ($this->_toFetch) {
            foreach ($results as $k => $result) {
                if (isset($result[$model->alias])) {
                    $id = $result[$model->alias]['id'];
                    $return = $this->optGet($model, $id, $this->_toFetch);

                    $results[$k][$model->alias] += $return;
                }
            }

            $this->_toFetch = array();
        }

        return $results;
    }

    public function beforeSave(&$model) {
        $keysToSave = $toSave = $toDelete = array();

        $fields = $this->_settings[$model->alias]['fields'];
        $dataKeys = array_keys($model->data[$model->alias]);

        $keysToSave = array_intersect($dataKeys, $fields);

        if ($keysToSave) {
            foreach ($keysToSave as $field) {
                if (!empty($model->data[$model->alias][$field])) {
                    $toSave[$field] = $model->data[$model->alias][$field];
                } else {
                    $toDelete[] = $field;
                }
            }
        }

        if ($toSave) {
            $this->_toSave = $toSave;
        }

        if ($toDelete) {
            $this->_toDelete = $toDelete;
        }

        return true;
    }

    public function afterSave(&$model, $created) {
        $id = $model->id;

        if (!$id) {
            return;
        }

        if ($this->_toSave) {
            $this->optSave($model, $id, $this->_toSave);
        }

        if ($this->_toDelete) {
            $this->optDelete($model, $id, $this->_toDelete);
        }

        $this->_toSave = $this->_toDelete = array();
    }

    /*public function afterDelete(&$model) {
        if ($model->id) {
            return $this->Model->deleteAll(array(
                'model' => $model->alias,
                'related_id' => $model->id
            ));
        }
    }*/

    public function optGet(&$model, $id = null, $fields = array()) {
        $return = array();

        if (!$id && !$fields) {
            $fields = $this->_settings[$model->alias]['fields'];
            $id = $model->id;
        }

        if (is_array($id)) {
            $fields = $id;
            $id = $model->id;
        }

        if ($id && $fields) {
            $conditions = array(
                'related_id' => $id,
                'model' => $model->alias,
                'opt_key' => $fields
            );

            $options = $this->Model->find('all', compact('conditions'));

            if ($options) {
                foreach ($options as $opt) {
                    $return[$opt[$this->_settings[$model->alias]['model']]['opt_key']] = unserialize($opt[$this->_settings[$model->alias]['model']]['opt_value']);
                }
            }

            if ($this->_settings[$model->alias]['emptyFields']) {
                foreach ($fields as $field) {
                    if (!isset($return[$field])) {
                        $return[$field] = null;
                    }
                }
            }
        }

        return $return;
    }

    public function optSave(&$model, $id = null, $fields = array()) {
        if (is_array($id)) {
            $fields = $id;
            $id = $model->id;
        }

        if ($id && $fields) {
            foreach ($fields as $key => $value) {
                $bypass = false;
                $value = serialize($value);
                $conditions = array(
                    'model' => $model->alias,
                    'related_id' => $id,
                    'opt_key' => $key
                );
                $data = $this->Model->find('first', compact('conditions'));

                if ($data) {
                    if ($value === $data[$this->_settings[$model->alias]['model']]['opt_value']) {
                        $bypass = true;
                    } else {
                        $data[$this->_settings[$model->alias]['model']]['opt_value'] = $value;
                    }
                } else {
                    $conditions['opt_value'] = $value;
                    $data = array($this->_settings[$model->alias]['model'] => $conditions);

                    $this->Model->create();
                }

                if (!$bypass) {
                    $this->Model->save($data);
                }
            }

            return true;
        }

        return false;
    }

    public function optDelete(&$model, $id = null, $fields = array()) {
        if (is_array($id)) {
            $fields = $id;
            $id = $model->id;
        }

        if ($id && $fields) {
            return $this->Model->deleteAll(array(
                'model' => $model->alias,
                'related_id' => $id,
                'opt_key' => $fields
            ));
        }

        return false;
    }
}