lithium\data\model\Query

class

The Query class acts as a container for all information necessary to perform a particular database operation. Each Query object instance has a type, which is usually one of 'create', 'read', 'update' or 'delete'.

Because of this, Query objects are the primary method of communication between Model classes and backend data sources. This helps to keep APIs abstract and flexible, since a model is only required to call a single method against its backend. Since the Query object simply acts as a structured data container, each backend can choose how to operate on the data the Query contains. See each class method for more details on what data this class supports.

Source

class Query extends \lithium\core\Object {

	/**
	 * Array containing mappings of relationship and field names, which allow database results to
	 * be mapped to the correct objects.
	 *
	 * @var array
	 */
	protected $_map = [];

	/**
	 * If a `Query` is bound to a `Record` or `Document` object (i.e. for a `'create'` or
	 * `'update'` query).
	 *
	 * @var object
	 */
	protected $_entity = null;

	/**
	 * An array of data used in a write context. Only used if no binding object is present in the
	 * `$_entity` property.
	 *
	 * @var array
	 */
	protected $_data = [];

	/**
	 * A query can be assigned its own custom schema object, using the `schema()` method. If this
	 * is not assigned, then the model associated with the query will be used to get the schema
	 * information.
	 *
	 * @var object
	 */
	protected $_schema = null;

	/**
	 * Classes used by `Query`.
	 *
	 * @var array
	 */
	protected $_classes = [
		'schema' => 'lithium\data\Schema'
	];

	/**
	 * The query's fields
	 *
	 * @see lithium\data\model\Query::fields()
	 * @var array
	 */
	protected $_fields = [0 => [], 1 => []];

	/**
	 * Count the number of identical models in a query for building
	 * unique aliases
	 *
	 * @see lithium\data\model\Query::alias()
	 * @var array
	 */
	protected $_alias = [];

	/**
	 * Map beetween generated aliases and corresponding relation paths
	 *
	 * @see lithium\data\model\Query::alias()
	 * @var array
	 */
	protected $_paths = [];

	/**
	 * Map beetween generated aliases and corresponding models.
	 *
	 * @see lithium\data\model\Query::alias()
	 * @var array
	 */
	protected $_models = [];

	/**
	 * Auto configuration properties.
	 *
	 * @var array
	 */
	protected $_autoConfig = ['map'];

	/**
	 * Initialization methods on construct
	 *
	 * @var array
	 */
	protected $_initializers = [
		'model', 'entity', 'conditions', 'having', 'group', 'order',
		'limit', 'offset', 'page', 'data', 'calculate', 'schema', 'comment'
	];

	/**
	 * Boolean indicate if the query is built or not
	 *
	 * @var string
	 */
	protected $_built = false;

	/**
	 * Constructor, which initializes the default values this object supports. Even though only
	 * a specific list of configuration parameters is available by default, the `Query` object
	 * uses the `__call()` method to implement automatic getters and setters for any arbitrary
	 * piece of data.
	 *
	 * This means that any information may be passed into the constructor may be used by the
	 * backend data source executing the query (or ignored, if support is not implemented).
	 * This is useful if, for example, you wish to extend a core data source and implement
	 * custom functionality.
	 *
	 * @param array $config Available configuration options are:
	 *        - `'type'` _string_: The type of the query (`read`, `create`, `update`, `delete`).
	 *        - `'mode'` _string_: `JOIN` mode for a join query.
	 *        - `'entity'` _object_: The base entity to query on. If set `'model'` is optionnal.
	 *        - `'model'` _string_: The base model to query on.
	 *        - `'source'` _string_: The name of the table/collection. Unnecessary
	 *          if `model` is set.
	 *        - `'alias'` _string_: Alias for the source. Unnecessary if `model` is set.
	 *        - `'schema'` _object_: A schema model. Unnecessary if `model` is set.
	 *        - `'fields'` _array_: The fields to retreive.
	 *        - `'conditions'` _array_: The conditions of the queries
	 *        - `'having'` _array_: The having conditions of the queries
	 *        - `'group'` _string_: The group by parameter.
	 *        - `'order'` _string_: The order by parameter.
	 *        - `'limit'` _string_: The limit parameter.
	 *        - `'offset'` _string_: The offset of the `limit` options.
	 *        - `'page'` _string_: Convenience parameter for setting the `offset`:
	 *          `offset` = `page` * `limit`.
	 *        - `'with'` _array_: Contain dependencies. Works only if `model` is set.
	 *        - `'joins'` _array_: Contain manual join dependencies.
	 *        - `'data'` _array_: Datas for update queries.
	 *        - `'whitelist'` _array_: Allowed fields for updating queries.
	 *        - `'calculate'` _string_: Alias name of the count.
	 *        - `'comment'` _string_: Comment for the query.
	 *        - `'map'` _object_: Unnecessary if `model` is set.
	 *        - `'relationships'` _array_: Unnecessary if `model` is set.
	 * @return void
	 */
	public function __construct(array $config = []) {
		$defaults = [
			'type' => 'read',
			'mode' => null,
			'model' => null,
			'entity' => null,
			'source' => null,
			'alias' => null,
			'fields' => [],
			'conditions' => [],
			'having' => [],
			'group' => null,
			'order' => null,
			'limit' => null,
			'offset' => null,
			'page' => null,
			'with' => [],
			'joins' => [],
			'data' => [],
			'whitelist' => [],
			'calculate' => null,
			'schema' => null,
			'comment' => null,
			'map' => [],
			'relationships' => []
		];
		parent::__construct($config + $defaults);
	}

	protected function _init() {
		parent::_init();

		foreach ($this->_initializers as $key) {
			if (($value = $this->_config[$key]) !== null) {
				$this->_config[$key] = is_array($value) ? [] : null;
				$this->{$key}($value);
			}
		}
		if ($list = $this->_config['whitelist']) {
			$this->_config['whitelist'] = array_combine($list, $list);
		}
		if ($this->_entity && !$this->_config['model']) {
			$this->model($this->_entity->model());
		}

		$this->with($this->_config['with']);

		if ($model = $this->model()) {
			$this->alias($this->_config['alias'] ?: $model::meta('name'));
		}
		$this->fields($this->_config['fields']);

		unset($this->_config['entity'], $this->_config['init']);
	}

	/**
	 * Generates a schema map of the query's result set, where the keys are aliases, and the values
	 * are arrays of field names.
	 *
	 * @param array $map
	 * @return array
	 */
	public function map($map = null) {
		if ($map !== null) {
			$this->_map = $map;
			return $this;
		}
		return $this->_map;
	}

	/**
	 * Accessor method for `Query` calculate values.
	 *
	 * @param string $calculate Value for calculate config setting.
	 * @return mixed Current calculate config value.
	 */
	public function calculate($calculate = null) {
		if ($calculate) {
			$this->_config['calculate'] = $calculate;
			return $this;
		}
		return $this->_config['calculate'];
	}

	/**
	 * Set or get the associated model.
	 *
	 * Will also set the source table, i.e. `$this->_config['source']` when setting the model.
	 *
	 * @param string|null $model Name of model to use, or `null` to retrieve current one.
	 * @return string|Query Either the current model name in use when $model is `null`,
	 *         or the query itself when setting the model name.
	 */
	public function model($model = null) {
		if (!$model) {
			return $this->_config['model'];
		}
		$this->_config['model'] = $model;
		$this->_config['source'] = $this->_config['source'] ?: $model::meta('source');

		return $this;
	}

	/**
	 * Set or append to existing conditions, or get current conditions.
	 *
	 * When getting current conditions and none are configured for the query,
	 * will ask the bound entity for its conditions instead.
	 *
	 * @param string|array|null $conditions Condition/s to append to existing conditions.
	 *        Provide `null` to get current conditions.
	 * @return string|Query Either the currrent conditions when $conditions is
	 *         `null` or the query itself when setting the conditions.
	 */
	public function conditions($conditions = null) {
		if (!$conditions) {
			return $this->_config['conditions'] ?: $this->_entityConditions();
		}
		$this->_config['conditions'] = array_merge(
			(array) $this->_config['conditions'], (array) $conditions
		);
		return $this;
	}

	/**
	 * Set and get _having_.
	 *
	 * @param mixed $having String or array to append to existing having.
	 * @return string|Query Either the currrent _having_ when $having is
	 *         `null` or the query itself when setting _having_.
	 */
	public function having($having = null) {
		if (!$having) {
			return $this->_config['having'];
		}
		$this->_config['having'] = array_merge(
			(array) $this->_config['having'], (array) $having
		);
		return $this;
	}

	/**
	 * Set, get or reset fields option for query.
	 *
	 * Usage:
	 * ```
	 * // to add a field
	 * $query->fields('created');
	 *
	 * // to add several fields
	 * $query->fields(['title','body','modified']);
	 *
	 * // to reset fields to none
	 * $query->fields(false);
	 * // should be followed by a 2nd call to fields with required fields
	 * ```
	 *
	 * @param mixed $fields string, array or `false`
	 * @param boolean $overwrite If `true`, existing fields will be removed before adding `$fields`.
	 * @return array Returns an array containing all fields added to the query.
	 */
	public function fields($fields = null, $overwrite = false) {
		if ($fields === false || $overwrite) {
			$this->_fields = [0 => [], 1 => []];
		}
		if ($fields === null) {
			return array_merge(array_keys($this->_fields[1]), $this->_fields[0]);
		}
		if (!$fields) {
			return $this;
		}
		foreach ((array) $fields as $key => $field) {
			if (is_string($field)) {
				$this->_fields[1][$field] = true;
			} elseif (is_array($field) && !is_numeric($key)) {
				foreach ($field as &$value) {
					$value = "{$key}.{$value}";
				}
				$this->fields($field);
			} else {
				$this->_fields[0][] = $field;
			}
		}
		return $this;
	}

	/**
	 * Set or get the limit for the amount of results to return.
	 *
	 * @param integer|boolean $limit An integer indicating the number of results to limit or
	 *        `false` to employ no limit at all. Or `null` to retrieve the current limit.
	 * @return integer|null|Query Either the currrent limit when $limit is
	 *         `null` or the query itself when setting the limit or providing `false`.
	 */
	public function limit($limit = null) {
		if ($limit) {
			$this->_config['limit'] = (integer) $limit;
			return $this;
		}
		if ($limit === false) {
			$this->_config['limit'] = null;
			return $this;
		}
		return $this->_config['limit'];
	}

	/**
	 * Set and get method for query's offset, i.e. which records to get
	 *
	 * @param integer|null $offset
	 * @return integer|\lithium\data\Query
	 */
	public function offset($offset = null) {
		if ($offset !== null) {
			$this->_config['offset'] = (integer) $offset;
			return $this;
		}
		return $this->_config['offset'];
	}

	/**
	 * Set and get method for page, in relation to limit, of which records to get
	 *
	 * @param integer|null $page
	 * @return integer|\lithium\data\Query
	 */
	public function page($page = null) {
		if ($page) {
			$this->_config['page'] = $page = ((integer) $page ?: 1);
			$this->offset(($page - 1) * $this->_config['limit']);
			return $this;
		}
		return $this->_config['page'];
	}

	/**
	 * Set and get method for the query's order specification.
	 *
	 * @param array|string|null $order
	 * @return array|\lithium\data\Query
	 */
	public function order($order = null) {
		if ($order) {
			$this->_config['order'] = $order;
			return $this;
		}
		return $this->_config['order'];
	}

	/**
	 * Set and get method for the `Query` group config setting.
	 *
	 * @param string|array|null $group
	 * @return array|null|\lithium\data\Query
	 */
	public function group($group = null) {
		if ($group) {
			$this->_config['group'] = $group;
			return $this;
		}
		if ($group === false) {
			$this->_config['group'] = null;
			return $this;
		}
		return $this->_config['group'];
	}

	/**
	 * Set and get method for current query's comment.
	 *
	 * Comment will have no effect on query, but will be passed along so data source can log it.
	 *
	 * @param string|null $comment
	 * @return string|\lithium\data\Query
	 */
	public function comment($comment = null) {
		if ($comment) {
			$this->_config['comment'] = $comment;
			return $this;
		}
		return $this->_config['comment'];
	}

	/**
	 * Set and get method for the query's entity instance.
	 *
	 * @param object $entity Reference to the query's current entity object.
	 * @return \lithium\data\Query|\lithium\data\Entity
	 */
	public function &entity(&$entity = null) {
		if ($entity) {
			$this->_entity = $entity;
			return $this;
		}
		return $this->_entity;
	}

	/**
	 * Set and get method for the query's record's data.
	 *
	 * @param array $data if set, will set given array.
	 * @return array Empty array if no data, array of data if the record has it.
	 */
	public function data($data = []) {
		$bind =& $this->_entity;

		if ($data) {
			$bind ? $bind->set($data) : $this->_data = array_merge($this->_data, $data);
			return $this;
		}
		$data = $bind ? $bind->data() : $this->_data;
		return ($list = $this->_config['whitelist']) ? array_intersect_key($data, $list) : $data;
	}

	/**
	 * Set and get the relationships.
	 *
	 * @param string $relpath A dotted path.
	 * @param array $config the config array to set.
	 * @return mixed The relationships array or a relationship array if `$relpath` is set. Returns
	 *         `null` if a join doesn't exist.
	 * @throws InvalidArgumentException
	 */
	public function relationships($relpath = null, $config = null) {
		if ($config) {
			if (!$relpath) {
				throw new InvalidArgumentException("The relation dotted path is empty.");
			}
			if (isset($config['model']) && isset($config['alias'])) {
				$this->_models[$config['alias']] = $config['model'];
			}
			$this->_config['relationships'][$relpath] = $config;
			return $this;
		}
		if (!$relpath) {
			return $this->_config['relationships'];
		}
		if (isset($this->_config['relationships'][$relpath])) {
			return $this->_config['relationships'][$relpath];
		}
	}

	/**
	 * Set and get the joins
	 *
	 * @param string $name Optional name of join. Unless two parameters are passed, this parameter
	 *               is regonized as `$join`.
	 * @param object|string $join A single query object or an array of query objects
	 * @return mixed The joins array or a join array if `$name` is set. Returns `null` if a join
	 *         doesn't exist.
	 */
	public function joins($name = null, $join = null) {
		if (is_array($name)) {
			$join = $name;
			$name = null;
		}
		if ($join) {
			if (!$name) {
				$this->_config['joins'][] = $join;
			} else {
				$this->_config['joins'][$name] = $join;
			}
			return $this;
		}
		if (!$name) {
			return $this->_config['joins'];
		}
		if (isset($this->_config['joins'][$name])) {
			return $this->_config['joins'][$name];
		}
	}


	/**
	 * Set and get method for the query's embed specification.
	 *
	 * @param array $with The dotted relation paths to embed
	 * @return mixed
	 */
	public function with($with = []) {
		if (!func_num_args()) {
			return $this->_config['with'];
		}
		if ((!$model = $this->model()) && $with) {
			throw new ConfigException("The `'with'` option needs a valid bound model.");
		}
		$this->_config['with'] = Set::normalize($with);
		return $this;
	}

	/**
	 * Convert the query's properties to the data sources' syntax and return it as an array.
	 *
	 * @param \lithium\data\Source $source Instance of the data source to use for conversion.
	 * @param array $options Options to use when exporting the data.
	 * @return array Returns an array containing a data source-specific representation of a query.
	 */
	public function export(Source $source, array $options = []) {
		$defaults = ['keys' => []];
		$options += $defaults;

		if ($options['keys']) {
			$keys = array_flip($options['keys']);
		} else {
			$keys =& $this->_config;
		}
		list($copy, $apply) = Set::slice($keys, $source->methods());

		if (isset($keys['with'])) {
			$this->applyStrategy($source);
		}

		foreach ($apply as $item => $value) {
			$results[$item] = $source->{$item}($this->{$item}(), $this);
		}
		foreach ($copy as $item => $value) {
			$results[$item] = $this->_config[$item];
		}

		if (array_key_exists('data', $keys)) {
			$results['data'] = $this->_exportData();
		}
		if (array_key_exists('source', $keys)) {
			$results['source'] = $source->name($results['source']);
		}

		if (!isset($results['fields'])) {
			return $results;
		}
		$created = ['fields', 'values'];

		if (is_array($results['fields']) && array_keys($results['fields']) == $created) {
			$results = $results['fields'] + $results;
		}
		return $results;
	}

	/**
	 * Helper method used by `export()` which delegate the query generation to the data source.
	 *
	 * @param \lithium\data\Source $source Instance of the data source to use for conversion.
	 */
	public function applyStrategy(Source $source) {
		if ($this->_built) {
			return;
		}
		$this->_built = true;
		if (!$this->_config['with']) {
			return;
		}
		$options = [];
		if (isset($this->_config['strategy'])) {
			$options['strategy'] = $this->_config['strategy'];
		}
		$source->applyStrategy($options, $this);
	}

	/**
	 * Helper method used by `export()` to extract the data either from a bound entity, or from
	 * passed configuration, and filter it through a configured whitelist, if present.
	 *
	 * @return array
	 */
	protected function _exportData() {
		$data = $this->_entity ? $this->_entity->export() : $this->_data;

		if (!$list = $this->_config['whitelist']) {
			return $data;
		}
		$list = array_combine($list, $list);

		if (!$this->_entity) {
			return array_intersect_key($data, $list);
		}

		foreach ($data as $type => $values) {
			if (!is_array($values)) {
				continue;
			}
			$data[$type] = array_intersect_key($values, $list);
		}
		return $data;
	}

	public function schema($field = null) {
		if (is_object($field)) {
			$this->_schema = $field;
			return;
		}
		if ($schema = $this->_schema) {
			return $field ? $schema[$field] : $schema;
		}
		if ($model = $this->model()) {
			return $model::schema($field);
		} else {
			return $this->_instance('schema');
		}
	}

	/**
	 * Get or Set a unique alias for the query or a query's relation if `$relpath` is set.
	 *
	 * @param mixed $alias The value of the alias to set for the passed `$relpath`. For getting an
	 *        alias value set alias to `true`.
	 * @param string $relpath A dotted relation name or `null` for identifying the query's model.
	 * @return string An alias value or `null` for an unexisting `$relpath` alias.
	 */
	public function alias($alias = true, $relpath = null) {
		if ($alias === true) {
			if (!$relpath) {
				return $this->_config['alias'];
			}
			$return = array_search($relpath, $this->_paths);
			return $return ?: null;
		}

		if ($relpath === null) {
			$this->_config['alias'] = $alias;
		}

		if ($relpath === null && ($model = $this->_config['model'])) {
			$this->_models[$alias] = $model;
		}

		$relpath = (string) $relpath;
		unset($this->_paths[array_search($relpath, $this->_paths)]);

		if (!$alias && $relpath) {
			$last = strrpos($relpath, '.');
			$alias = $last ? substr($relpath, $last + 1) : $relpath;
		}

		if (isset($this->_alias[$alias])) {
			$this->_alias[$alias]++;
			$alias .= '__' . $this->_alias[$alias];
		} else {
			$this->_alias[$alias] = 1;
		}

		$this->_paths[$alias] = $relpath;
		return $alias;
	}

	/**
	 * Return the generated aliases mapped to their relation path
	 *
	 * @param \lithium\data\Source $source Instance of the data source to use for conversion.
	 * @return array Map between aliases and their corresponding dotted relation paths.
	 */
	public function paths(Source $source = null) {
		if ($source) {
			$this->applyStrategy($source);
		}
		return $this->_paths;
	}

	/**
	 * Return the generated aliases mapped to their corresponding model
	 *
	 * @param \lithium\data\Source $source Instance of the data source to use for conversion.
	 * @return array Map between aliases and their corresponding fully-namespaced model names.
	 */
	public function models(Source $source = null) {
		if ($source) {
			$this->applyStrategy($source);
		}
		return $this->_models;
	}

	/**
	 * Gets or sets a custom query field which does not have an accessor method.
	 *
	 * @param string $method Query part.
	 * @param array $params Query parameters.
	 * @return mixed Returns the value as set in the `Query` object's constructor.
	 */
	public function __call($method, array $params = []) {
		if ($params) {
			$this->_config[$method] = current($params);
			return $this;
		}
		return isset($this->_config[$method]) ? $this->_config[$method] : null;
	}

	/**
	 * Determines if a given method can be called.
	 *
	 * @param string $method Name of the method.
	 * @param boolean $internal Provide `true` to perform check from inside the
	 *                class/object. When `false` checks also for public visibility;
	 *                defaults to `false`.
	 * @return boolean Returns `true` if the method can be called, `false` otherwise.
	 */
	public function respondsTo($method, $internal = false) {
		return isset($this->_config[$method]) || parent::respondsTo($method, $internal);
	}

	/**
	 * Will return a find first condition on the associated model if a record is connected.
	 * Called by conditions when it is called as a get and no condition is set.
	 *
	 * @return array Returns an array in the following format:
	 *         `([model's primary key'] => [that key set in the record])`.
	 */
	protected function _entityConditions() {
		if (!$this->_entity || !($model = $this->_config['model'])) {
			return [];
		}
		$key = $model::key($this->_entity->data());

		if (!$key && $this->type() !== 'create') {
			throw new ConfigException('No matching primary key found.');
		}
		if (is_array($key)) {
			return $key;
		}

		$key = $model::meta('key');
		$val = $this->_entity->{$key};
		return $val ? [$key => $val] : [];
	}

	/**
	 * Get/set sub queries for the query.
	 *
	 * The getter must be called after an export since the sub queries are built
	 * during the export according the export's `mode` option and the query `with` option.
	 *
	 * @see lithium\data\model\Query::export()
	 * @param string $relpath a dotted relation path
	 * @param string $query a query instance
	 * @return mixed
	 */
	public function childs($relpath = null, $query = null) {
		if (!$model = $this->model()) {
			throw new ConfigException('No bound model.');
		}
		if ($query) {
			$this->_childs[$relpath] = $query;
			return $this;
		}
		return $this->_childs;
	}
}