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<?php namespace Illuminate\Database\Eloquent\Relations;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Database\Query\Expression;
use Illuminate\Database\Eloquent\Collection;
class HasManyThrough extends Relation {
/**
* The distance parent model instance.
*
* @var \Illuminate\Database\Eloquent\Model
*/
protected $farParent;
/**
* The near key on the relationship.
*
* @var string
*/
protected $firstKey;
/**
* The far key on the relationship.
*
* @var string
*/
protected $secondKey;
/**
* Create a new has many relationship instance.
*
* @param \Illuminate\Database\Eloquent\Builder $query
* @param \Illuminate\Database\Eloquent\Model $parent
* @param string $firstKey
* @param string $secondKey
* @return void
*/
public function __construct(Builder $query, Model $farParent, Model $parent, $firstKey, $secondKey)
{
$this->firstKey = $firstKey;
$this->secondKey = $secondKey;
$this->farParent = $farParent;
parent::__construct($query, $parent);
}
/**
* Set the base constraints on the relation query.
*
* @return void
*/
public function addConstraints()
{
$parentTable = $this->parent->getTable();
$this->setJoin();
if (static::$constraints)
{
$this->query->where($parentTable.'.'.$this->firstKey, '=', $this->farParent->getKey());
}
}
/**
* Add the constraints for a relationship count query.
*
* @param \Illuminate\Database\Eloquent\Builder $query
* @param \Illuminate\Database\Eloquent\Builder $parent
* @return \Illuminate\Database\Eloquent\Builder
*/
public function getRelationCountQuery(Builder $query, Builder $parent)
{
$parentTable = $this->parent->getTable();
$this->setJoin($query);
$query->select(new Expression('count(*)'));
$key = $this->wrap($parentTable.'.'.$this->firstKey);
return $query->where($this->getHasCompareKey(), '=', new Expression($key));
}
/**
* Set the join clause on the query.
*
* @param \Illuminate\Database\Eloquent\Builder|null $query
* @return void
*/
protected function setJoin(Builder $query = null)
{
$query = $query ?: $this->query;
$foreignKey = $this->related->getTable().'.'.$this->secondKey;
$query->join($this->parent->getTable(), $this->getQualifiedParentKeyName(), '=', $foreignKey);
}
/**
* Set the constraints for an eager load of the relation.
*
* @param array $models
* @return void
*/
public function addEagerConstraints(array $models)
{
$table = $this->parent->getTable();
$this->query->whereIn($table.'.'.$this->firstKey, $this->getKeys($models));
}
/**
* Initialize the relation on a set of models.
*
* @param array $models
* @param string $relation
* @return array
*/
public function initRelation(array $models, $relation)
{
foreach ($models as $model)
{
$model->setRelation($relation, $this->related->newCollection());
}
return $models;
}
/**
* Match the eagerly loaded results to their parents.
*
* @param array $models
* @param \Illuminate\Database\Eloquent\Collection $results
* @param string $relation
* @return array
*/
public function match(array $models, Collection $results, $relation)
{
$dictionary = $this->buildDictionary($results);
// Once we have the dictionary we can simply spin through the parent models to
// link them up with their children using the keyed dictionary to make the
// matching very convenient and easy work. Then we'll just return them.
foreach ($models as $model)
{
$key = $model->getKey();
if (isset($dictionary[$key]))
{
$value = $this->related->newCollection($dictionary[$key]);
$model->setRelation($relation, $value);
}
}
return $models;
}
/**
* Build model dictionary keyed by the relation's foreign key.
*
* @param \Illuminate\Database\Eloquent\Collection $results
* @return array
*/
protected function buildDictionary(Collection $results)
{
$dictionary = array();
$foreign = $this->farParent->getForeignKey();
// First we will create a dictionary of models keyed by the foreign key of the
// relationship as this will allow us to quickly access all of the related
// models without having to do nested looping which will be quite slow.
foreach ($results as $result)
{
$dictionary[$result->{$foreign}][] = $result;
}
return $dictionary;
}
/**
* Get the results of the relationship.
*
* @return mixed
*/
public function getResults()
{
return $this->get();
}
/**
* Execute the query as a "select" statement.
*
* @param array $columns
* @return \Illuminate\Database\Eloquent\Collection
*/
public function get($columns = array('*'))
{
// First we'll add the proper select columns onto the query so it is run with
// the proper columns. Then, we will get the results and hydrate out pivot
// models with the result of those columns as a separate model relation.
$select = $this->getSelectColumns($columns);
$models = $this->query->addSelect($select)->getModels();
// If we actually found models we will also eager load any relationships that
// have been specified as needing to be eager loaded. This will solve the
// n + 1 query problem for the developer and also increase performance.
if (count($models) > 0)
{
$models = $this->query->eagerLoadRelations($models);
}
return $this->related->newCollection($models);
}
/**
* Set the select clause for the relation query.
*
* @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
*/
protected function getSelectColumns(array $columns = array('*'))
{
if ($columns == array('*'))
{
$columns = array($this->related->getTable().'.*');
}
return array_merge($columns, array($this->parent->getTable().'.'.$this->firstKey));
}
/**
* Get the key name of the parent model.
*
* @return string
*/
protected function getQualifiedParentKeyName()
{
return $this->parent->getQualifiedKeyName();
}
/**
* Get the key for comparing against the parent key in "has" query.
*
* @return string
*/
public function getHasCompareKey()
{
return $this->farParent->getQualifiedKeyName();
}
}
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