A MoreLikeThis (MLT) query is designed to generate information about "similar" documents using the MoreLikeThis functionality provided by Lucene. It supports faceting, paging, and filtering using CommonQueryParameters.

This query uses the Solr MoreLikeThis Handler that specifically returns MLT results. Alternatively you can use the MLT component for the select query.

Building a MLT query

See the example code below.

Available options:

Name	Type	Default value	Description
handler	string	select	Name of the Solr request handler to use, without leading or trailing slashes
resultclass	string	Solarium_Result_Select	Classname for result. If you set a custom classname make sure the class is readily available (or through autoloading)
documentclass	string	Solarium_Document_ReadWrite	Classname for documents in the resultset. If you set a custom classname make sure the class is readily available (or through autoloading)
query	string	*:*	Query to execute
start	int	0	Start position (offset) in the complete Solr query resultset, to paginate big resultsets.
rows	integer	10	Number of rows to fetch, starting from the 'start' (offset) position. It's a limit, you might get less.
fields	string	- ,score	Comma separated list of fields to fetch from Solr. There are two special values: '*' meaning 'all fields' and 'score' to also fetch the Solr document score value.
sort	array	empty array	Array with sort field as key and sort order as values. Multiple entries possible, they are used in the order of the array. Example: array('price' => 'asc')
stream	boolean	false	Set to true to post query content instead of using the URL param
interestingTerms	string	none	Must be one of: none, list, details
matchinclude	boolean	false
mltfields	string	none	The fields to use for similarity. NOTE: if possible, these should have a stored TermVector
minimumtermfrequency	int	none
minimumdocumentfrequency	int	none
minimumwordlength	int	none
maximumwordlength	int	none
maximumqueryterms	int	none
maximumnumberoftokens	int	none
boost	boolean	none	If true the query will be boosted by the interesting term relevance
queryfields	string	none	Query fields and their boosts using the same format as that used in DisMaxQParserPlugin. These fields must also be specified in fields.

Executing a MLT query

Use the moreLikeThis method of the client to execute the query object. See the example code below.

Result of a MLT query

The result of a mlt query shares the features of the select query result. On top of that the following is added:

Interestingterms

This will show what "interesting" terms are used for the MoreLikeThis query.

Match

Get matched documents. Only available if matchinclude was set to true in the query.

Example

<?php

require_once(__DIR__.'/init.php');
use Solarium\Client;

htmlHeader();

// create a client instance
$client = new Client($adapter, $eventDispatcher, $config);

// get a morelikethis query instance
$query = $client->createMoreLikeThis();

$query->setQuery('id:SP2514N');
$query->setMltFields('manu,cat');
$query->setMinimumDocumentFrequency(1);
$query->setMinimumTermFrequency(1);
$query->createFilterQuery('stock')->setQuery('inStock:true');
$query->setInterestingTerms('details');
$query->setMatchInclude(true);

// enable mlt component
$mlt = $query->getMoreLikeThis();
$mlt->setCount(10);

// this executes the query and returns the result
$resultset = $client->select($query);

echo 'Document used for matching:<br/><table>';
foreach ($resultset->getMatch() as $field => $value) {
    // this converts multivalue fields to a comma-separated string
    if (is_array($value)) {
        $value = implode(', ', $value);
    }

    echo '<tr><th>' . $field . '</th><td>' . $value . '</td></tr>';
}
echo '</table><hr/>';

// display the total number of MLT documents found by solr
echo 'Number of MLT matches found: '.$resultset->getNumFound().'<br/><br/>';
echo '<b>Listing of matched docs:</b>';

// show MLT documents using the resultset iterator
foreach ($resultset as $document) {

    echo '<hr/><table>';

    // the documents are also iterable, to get all fields
    foreach ($document as $field => $value) {
        // this converts multivalue fields to a comma-separated string
        if (is_array($value)) {
            $value = implode(', ', $value);
        }

        echo '<tr><th>' . $field . '</th><td>' . $value . '</td></tr>';
    }

    echo '</table>';
}

htmlFooter();