/**
* Modify the given query object to account for some property condition for
* the given property. If it is not possible to generate a query for the
* given data, the query type is changed to QueryContainer::Q_NOQUERY. Callers need
* to check for this and discard the query in this case.
*
* @note This method does not support sortkey (_SKEY) property queries,
* since they do not have a normal property table. This should not be a
* problem since comparators on sortkeys are supported indirectly when
* using comparators on wikipages. There is no reason to create any
* query with _SKEY ad users cannot do so either (no user label).
*
* @since 1.8
*/
private function interpretPropertyConditionForDescription(QuerySegment $query, SomeProperty $description)
{
$db = $this->querySegmentListBuilder->getStore()->getConnection('mw.db');
$property = $description->getProperty();
$tableid = $this->querySegmentListBuilder->getStore()->findPropertyTableID($property);
if ($tableid === '') {
// Give up
$query->type = QuerySegment::Q_NOQUERY;
return;
}
$proptables = $this->querySegmentListBuilder->getStore()->getPropertyTables();
$proptable = $proptables[$tableid];
if (!$proptable->usesIdSubject()) {
// no queries with such tables
// (only redirects are affected in practice)
$query->type = QuerySegment::Q_NOQUERY;
return;
}
$typeid = $property->findPropertyTypeID();
$diType = DataTypeRegistry::getInstance()->getDataItemId($typeid);
if ($property->isInverse() && $diType !== DataItem::TYPE_WIKIPAGE) {
// can only invert properties that point to pages
$query->type = QuerySegment::Q_NOQUERY;
return;
}
$diHandler = $this->querySegmentListBuilder->getStore()->getDataItemHandlerForDIType($diType);
$indexField = $diHandler->getIndexField();
// TODO: strictly speaking, the DB key is not what we want here,
// since sortkey is based on a "wiki value"
$sortkey = $property->getKey();
// *** Now construct the query ... ***//
$query->joinTable = $proptable->getName();
// *** Add conditions for selecting rows for this property ***//
if (!$proptable->isFixedPropertyTable()) {
$pid = $this->querySegmentListBuilder->getStore()->getObjectIds()->getSMWPropertyID($property);
// Construct property hierarchy:
$pqid = QuerySegment::$qnum;
$pquery = new QuerySegment();
$pquery->type = QuerySegment::Q_PROP_HIERARCHY;
$pquery->joinfield = array($pid);
$query->components[$pqid] = "{$query->alias}.p_id";
$pquery->segmentNumber = $pqid;
$this->querySegmentListBuilder->addQuerySegment($pquery);
// Alternative code without property hierarchies:
// $query->where = "{$query->alias}.p_id=" . $this->m_dbs->addQuotes( $pid );
}
// else: no property column, no hierarchy queries
// *** Add conditions on the value of the property ***//
if ($diType === DataItem::TYPE_WIKIPAGE) {
$o_id = $indexField;
if ($property->isInverse()) {
$s_id = $o_id;
$o_id = 's_id';
} else {
$s_id = 's_id';
}
$query->joinfield = "{$query->alias}.{$s_id}";
// process page description like main query
$sub = $this->querySegmentListBuilder->buildQuerySegmentFor($description->getDescription());
if ($sub >= 0) {
$query->components[$sub] = "{$query->alias}.{$o_id}";
}
if (array_key_exists($sortkey, $this->querySegmentListBuilder->getSortKeys())) {
// TODO: This SMW IDs table is possibly duplicated in the query.
// Example: [[has capital::!Berlin]] with sort=has capital
// Can we prevent that? (PERFORMANCE)
$query->from = ' INNER JOIN ' . $db->tableName(SMWSql3SmwIds::TABLE_NAME) . " AS ids{$query->alias} ON ids{$query->alias}.smw_id={$query->alias}.{$o_id}";
$query->sortfields[$sortkey] = "ids{$query->alias}.smw_sortkey";
}
} else {
// non-page value description
$query->joinfield = "{$query->alias}.s_id";
$this->interpretInnerValueDescription($query, $description->getDescription(), $proptable, $diHandler, 'AND');
if (array_key_exists($sortkey, $this->querySegmentListBuilder->getSortKeys())) {
$query->sortfields[$sortkey] = "{$query->alias}.{$indexField}";
}
}
}
