What is hydration teaching?

Question

I read about hydration in the documentation of the doctrine, but I still don't understand what it is.

Can someone explain?

Answer 1

Hydration is a method used to return query results. For example:

• HYDRATE_ARRAY - This will return you an array of records that are represented by another array:

   $q = Doctrine_Query::create() ->from('Post p') ->setHydrationMode(Doctrine::HYDRATE_ARRAY); $resultSet = $q->execute(); // $resultSet is an array foreach ($resultSet as $post) { // $post is an array echo $post['title']; } 

• HYDRATE_RECORD - This will return you a collection ( Doctrine_Collection ) of objects:

   $q = Doctrine_Query::create() ->from('Post p') ->setHydrationMode(Doctrine::HYDRATE_RECORD); // Unnecessary, HYDATE_RECORD is default method $resultSet = $q->execute(); // $resultSet is an Doctrine_Collection object foreach ($resultSet as $post) { // $post is an Post object echo $post->getTitle(); echo $post['title']; // Each Doctrine Model object implements ArrayAccess interface so this is possible echo $post->myCustomMethod(); } 

• HYDRATE_SINGULAR_SCALAR - will return the value of the first column of the query result:

    $q = Doctrine_Query::create() ->select('p.created_at') ->from('Post p') ->where('p.id = ?', 321) ->setHydrationMode(Doctrine::HYDRATE_SINGULAR_SCALAR); $createdAt = $q->execute(); // $createdAt has value of first column from first record from result set (eg.: 2008-04-06 21:22:35) 

There are several more methods that you can read about in the documentation.

Answer 2

Link to Doctrine2 documentation explaining HYDRATION: http://www.doctrine-project.org/docs/orm/2.0/en/reference/dql-doctrine-query-language.html#query-result-formats

Answer 3

 $q->fetchOne(array(), Doctrine_Core::HYDRATE_ARRAY); 

It will return a simple array instead of a doctrine collection object.