In Zend app, I use Zend\Db\TableGateway
and Zend\Db\Sql
to retrieve data data from MySQL database as below.
Model -
public function getCandidateEduQualifications($id)
{
$id = (int) $id;
$rowset = $this->tableGateway->select(function (Sql\Select $select) use ($id)
{
$select->where
->AND->NEST->equalTo('candidate_id', $id)
->AND->equalTo('qualification_category', 'Educational');
});
return $rowset;
}
View -
I just iterate $rowset and echo in view. But it gives error when try to echo two or more times. Single iteration works.
This result is a forward only result set, calling rewind() after moving forward is not supported
I can solve it by loading it to another array in view. But is it the best way ? Is there any other way to handle this ?
$records = array();
foreach ($edu_qualifications as $result) {
$records[] = $result;
}
EDIT -
$resultSet->buffer();
solved the problem.
This worked for me.
Sure, It looks like when we use Mysql and want to iterate $resultSet, this error will happen, b/c Mysqli only does forward-moving result sets (Refer to this post: ZF2 DB Result position forwarded?)
I came across this problem too. But when add following line, it solved:
but in this mentioned post, it suggest use following line. I just wonder why, and what's difference of them:
You receive this
Exception
because this is expected behavior. Zend uses PDO to obtain itsZend\Db\ResultSet\Resultset
which is returned byZend\Db\TableGateway\TableGateway
. PDO result sets use a forward-only cursor by default, meaning you can only loop through the set once.For more information about cursors check Wikipedia and this article.
As the
Zend\Db\ResultSet\Resultset
implements the PHPIterator
you can extract an array of the set using theZend\Db\ResultSet\Resultset:toArray()
method or using theiterator_to_array()
function. Do be careful though about using this function on potentially large datasets! One of the best things about cursors is precisely that they avoid bringing in everything in one go, in case the data set is too large, so there are times when you won't want to put it all into an array at once.