Select One column Doctrine DQL

Question

I need a simple column for a table.

By example a table "project", with column id, name and year.

If I do:

$q = Doctrine_Query::create()
        ->select('a.pro_id')
        ->from('fndr_proyecto a')
        ->where('a.pro_id =?',1);
    $pro = $q->execute();
    json_encode($pro->toArray());

The answer is all column like

{"id":1,"name":"Project name","year":2013}

but I need only one column. I expect:

{"id":1}

It is with DQL because with native SQL work fine.

The ORM is build automaticaly with a Visual Paradigm.

Lend

Answer 1

This is because Doctrine hydrate the response with all the object information, so all columns.

You need to use a different hydration method, there are many one, but let's focus on 5 of them:

• HYDRATE_RECORD, the default one
• HYDRATE_ARRAY
• HYDRATE_NONE
• HYDRATE_SCALAR
• HYDRATE_ARRAY_SHALLOW

You need the HYDRATE_ARRAY_SHALLOW hydration method. Here's why.

1. HYDRATE_RECORD

   $q = Doctrine_Query::create()
       ->select('a.pro_id')
       ->from('fndr_proyecto a')
       ->where('a.pro_id = ?',1);
   $pro = $q->execute(array(), Doctrine_Core::HYDRATE_RECORD);
   var_dump(json_encode($pro->toArray()));
   

   This will hydrate the result using object, and also hydrate relations (if you use a leftJoin inside your query). Since it returns object, we need to call toArray() to be able to send a propre json:

   [{"id":1,"name":"Project name","year":2013}]"
   

2. HYDRATE_ARRAY

   $q = Doctrine_Query::create()
       ->select('a.pro_id')
       ->from('fndr_proyecto a')
       ->where('a.pro_id = ?',1);
   $pro = $q->execute(array(), Doctrine_Core::HYDRATE_ARRAY);
   var_dump(json_encode($pro));
   

   This will hydrate result as an array an automatically add the primary key:

   [{"id":"1","pro_id":"1"}]"
   

3. HYDRATE_NONE

   $q = Doctrine_Query::create()
       ->select('a.pro_id')
       ->from('fndr_proyecto a')
       ->where('a.pro_id = ?',1);
   $pro = $q->execute(array(), Doctrine_Core::HYDRATE_NONE);
   var_dump(json_encode($pro));
   

   This won't hydrate result, and return just values:

   [["1"]]"
   

4. HYDRATE_SCALAR

   $q = Doctrine_Query::create()
       ->select('a.pro_id')
       ->from('fndr_proyecto a')
       ->where('a.pro_id = ?',1);
   $pro = $q->execute(array(), Doctrine_Core::HYDRATE_SCALAR);
   var_dump(json_encode($pro));
   

   This will hydrate result from the select but with key index as the column name with the table alias:

   [{"a_pro_id":"1"}]"
   

5. HYDRATE_ARRAY_SHALLOW

   $q = Doctrine_Query::create()
       ->select('a.pro_id')
       ->from('fndr_proyecto a')
       ->where('a.pro_id = ?',1);
   $pro = $q->execute(array(), Doctrine_Core::HYDRATE_ARRAY_SHALLOW);
   var_dump(json_encode($pro));
   

   This will hydrate result from the select but with key index as the column name without the table alias:

   "[{"pro_id":"1"}]"
   

Wilone

Of course! Now find the chapter in the documentation "Data Hydrators". I did not know of that it was about the subject. Thank you very much! ;) – Lend

@Lend try them, array hydration is often faster and lighter than record hydration ! – Wilone

Very good explanation, I've always been puzzled about how works the hydrators, but now all is clear in my mind. Thanks ! – Lapides

Answer 2

As of Doctrine 2.10, you can use Scalar Column Hydration:

$query = $em->createQuery('SELECT a.id FROM CmsUser u');
$ids = $query->getResult(Query::HYDRATE_SCALAR_COLUMN);

or

$ids = $query->getSingleColumnResult();

and this results in a flat array

[412, 959, 1234]

Chartulary

Answer 3

I'm not sure what version of Doctrine j0k was using. It provided some answers, but I did have trouble finding Doctrine_Query and Doctrine_Core classes. I am using Doctrine 2.3.4. The following worked for me.

public static function getAllEventIDs($em) {
    return parent::getAllFromColumn('\path\to\Entity\entityName', 'id', $em);
}

public static function getAllFromColumn($tableName, $columnName, $em) {
    $q = $em->createQueryBuilder('t')
    ->select("t.$columnName")
    ->from($tableName, 't');

    $q = $q->getQuery();

    $result = $q->getResult(\Doctrine\ORM\Query::HYDRATE_SCALAR);

    return $result;
}

This did however return a array of arrays. ie, the id of the first event was is

$result[0]['id'];

Retrospection