Convert Zend\Db\ResultSet\HydratingResultSet to Array of Objects

问题

In my Mapper class I'm extending AbstractDbMapper from ZfcBase to fetch rows from the database. A simple example would be code like this:

class MyMapper extends AbstractDbMapper
{

    //...

    public function fetchAll() {
        $select = $this->getSelect();
        return $this->select($select); // returns HydratingResultSet
    }
}

The problem is that $this->select() returns a Zend\Db\ResultSet\HydratingResultSet (containing the needed and hydrated objects). But I would like to return an array of these objects instead of a HydratingResultSet containing the objects.

The first thing to look at would be HydratingResultSet::toArray() but this returns a multidimensional array instead of an array of objects.

So I chose to do it by hand:

public function fetchAll() {
        $select = $this->getSelect();

        $results = array();
        foreach ($this->select($select) as $object) {
            $results[] = $object;
        }
        return $results; // returns array of needed objects
}

This works but looks ugly in every fetch method. Do I have to modify the code from select() to get the wanted behavior or is there an easier way?

Btw: Is it even recommended to return an array or convert it like this? Thanks for your help!

回答1:

Update:

There is a cleaner possibility to do it (by limos from https://stackoverflow.com/a/19266650/1275778). Adapted to my example from above it works like this:

public function fetchAll() {
    $select = $this->getSelect();
    $results = $this->select($select);
    return \Zend\Stdlib\ArrayUtils::iteratorToArray($results); // returns desired array of objects
}

If limos posts his answer here, I will happily accept it.

Old answer:

Since no one could answer my question I tried to implement the cleanest option (to me): extending AbstractDbMapper to add the mentioned functionality. I document it here for anyone looking for a solution:

MyAbstractDbMapper extends AbstractDbMapper
{
    /**
     * @param Select $select
     * @param object|null $entityPrototype
     * @param HydratorInterface|null $hydrator
     * @return array
     */
    protected function select(Select $select, $entityPrototype = null, 
        HydratorInterface $hydrator = null)
    {
        $resultSet = parent::select($select, $entityPrototype, $hydrator);
        $results = array(); // Array of result objects
        foreach ($resultSet as $object) {
            $results[] = $object;
        }
        return $results;
    }
}

select() in MyAbstractDbMapper now returns an array of objects instead of HydratingResultSet.

As this is getting downvoted, could someone please explain why?

回答2:

usually you've already got the object class anyway so just popupate instances of your object (class):

public function fetchById($id) {

    [...]

    $resultSet = $this->getDbTable()->fetchAll($select);
    $entries   = array();

    foreach ($resultSet as $row) {
        $entries[] = $this->populate($row);
    }

    return $entries;
}

and the populate function could look something like this:

private function populate($row)
{
    $entry = new Application_Model_YourModel();

    $entry->setId($row->id);

    [...] //set other object values

    return $entry;
}

This will return an array of objects

来源：https://stackoverflow.com/questions/16590174/convert-zend-db-resultset-hydratingresultset-to-array-of-objects

标签

zend-framework

zend-framework2

zend-db