Exact search query with Elastica QueryBuilder - php

Question

I'm having a problem with an Elastica QueryBuilder exact search in a Symfony app. The Elastica version is 2.1, which depends on Elasticsearch 1.5.2. I'm searching an index where one of the fields is mapped as
majors:
type: string
index : not_analyzed
The field is a student's major that can have one or more words, such as "Ancient History".
The query is set up like this:
/** #var ElasticaFactory $ef */
protected $ef;
public function __construct(ElasticaFactory $ef)
{
$this->ef = $ef;
}
$query = $this->ef->createQuery();
$qb = $this->ef->createQueryBuilder();
$bool = $qb->filter()->bool();
$query->setQuery(
$qb->query()->filtered(
$qb->query()->term(),
$bool->addShould(
$qb->filter()->term(
array('majors' => $params['majors'])
)
)
)
);
When I run this query, I get a SearchPhaseExecutionException error. The full text of the error message is here.
Stack trace shows the full contents of the request:
Client ->request ('students/_search', 'GET', array('query' => array('filtered' => array('query' => array('term' => array()), 'filter' => array('bool' => array('should' => array(array('term' => array('majors' => 'Ancient Studies')))))))), array('from' => '0', 'size' => '10'))
in /vagrant/persona/vendor/ruflin/elastica/lib/Elastica/Search.php at line 455
When I set up the query as a "match" below, it works with no errors:
$query->setQuery(
$qb->query()->filtered(
$qb->query()->match('majors', $params['majors']),
$bool
)
);
However, a match query returns too many irrelevant results. I need specifically an exact search query.
Next, in order to eliminate any issues with Elastica, I converted the query into a raw ES query, like this:
$query->setRawQuery(
array(
'query' => array(
'filtered' => array(
'query' => array(
'term' => array()),
'filter' => array(
'bool' => array(
'should' => array(
array(
'term' => array(
'majors' => 'Art History'
)
)
)
)
)
)
)
)
);
This gave me the same error message as quoted above. Looks like there is a problem with the query itself, and not with Elastica.
When I rearranged the query to exactly follow the documentation as below, it returned no results, even though matching records were present
$query->setRawQuery(
array(
'query' => array(
'filtered' => array(
'filter' => array(
'term' => array(
'majors' => 'Art History'
)
)
)
)
)
);
Any help would be appreciated!