/**
* Helper function for reading all data for from a given property table
* (specified by an SMWSQLStore3Table object), based on certain
* restrictions. The function can filter data based on the subject (1)
* or on the property it belongs to (2) -- but one of those must be
* done. The Boolean $issubject is true for (1) and false for (2).
*
* In case (1), the first two parameters are taken to refer to a
* subject; in case (2) they are taken to refer to a property. In any
* case, the retrieval is limited to the specified $proptable. The
* parameters are an internal $id (of a subject or property), and an
* $object (being an SMWDIWikiPage or SMWDIProperty). Moreover, when
* filtering by property, it is assumed that the given $proptable
* belongs to the property: if it is a table with fixed property, it
* will not be checked that this is the same property as the one that
* was given in $object.
*
* In case (1), the result in general is an array of pairs (arrays of
* size 2) consisting of a property key (string), and DB keys (array if
* many, string if one) from which a datvalue object for this value can
* be built. It is possible that some of the DB keys are based on
* internal objects; these will be represented by similar result arrays
* of (recursive calls of) fetchSemanticData().
*
* In case (2), the result is simply an array of DB keys (array)
* without the property keys. Container objects will be encoded with
* nested arrays like in case (1).
*
* @todo Maybe share DB handler; asking for it seems to take quite some
* time and we do not want to change it in one call.
*
* @since 1.8
* @param integer $id
* @param SMWDataItem $object
* @param SMWSQLStore3Table $proptable
* @param boolean $issubject
* @param SMWRequestOptions $requestoptions
*
* @return array
*/
protected function fetchSemanticData($id, SMWDataItem $object = null, SMWSQLStore3Table $proptable, $issubject = true, SMWRequestOptions $requestoptions = null)
{
// stop if there is not enough data:
// properties always need to be given as object,
// subjects at least if !$proptable->idsubject
if ($id == 0 || is_null($object) && (!$issubject || !$proptable->usesIdSubject())) {
return array();
}
wfProfileIn("SMWSQLStore3::fetchSemanticData-" . $proptable->getName() . " (SMW)");
$result = array();
$db = wfGetDB(DB_SLAVE, 'smw');
$diHandler = $this->store->getDataItemHandlerForDIType($proptable->getDiType());
// *** First build $from, $select, and $where for the DB query ***//
$from = $db->tableName($proptable->getName());
// always use actual table
$select = '';
$where = '';
if ($issubject) {
// restrict subject, select property
$where .= $proptable->usesIdSubject() ? 's_id=' . $db->addQuotes($id) : 's_title=' . $db->addQuotes($object->getDBkey()) . ' AND s_namespace=' . $db->addQuotes($object->getNamespace());
if (!$proptable->isFixedPropertyTable()) {
// select property name
$from .= ' INNER JOIN ' . $db->tableName(SMWSql3SmwIds::tableName) . ' AS p ON p_id=p.smw_id';
$select .= 'p.smw_title as prop';
}
// else: fixed property, no select needed
} elseif (!$proptable->isFixedPropertyTable()) {
// restrict property only
$where .= 'p_id=' . $db->addQuotes($id);
}
$valuecount = 0;
// Don't use DISTINCT for value of one subject:
$usedistinct = !$issubject;
$valueField = $diHandler->getIndexField();
$labelField = $diHandler->getLabelField();
$fields = $diHandler->getFetchFields();
foreach ($fields as $fieldname => $typeid) {
// select object column(s)
if ($typeid == 'p') {
// get data from ID table
$from .= ' INNER JOIN ' . $db->tableName(SMWSql3SmwIds::tableName) . " AS o{$valuecount} ON {$fieldname}=o{$valuecount}.smw_id";
$select .= ($select !== '' ? ',' : '') . "{$fieldname} AS id{$valuecount}" . ",o{$valuecount}.smw_title AS v{$valuecount}" . ",o{$valuecount}.smw_namespace AS v" . ($valuecount + 1) . ",o{$valuecount}.smw_iw AS v" . ($valuecount + 2) . ",o{$valuecount}.smw_sortkey AS v" . ($valuecount + 3) . ",o{$valuecount}.smw_subobject AS v" . ($valuecount + 4);
if ($valueField == $fieldname) {
$valueField = "o{$valuecount}.smw_sortkey";
}
if ($labelField == $fieldname) {
$labelField = "o{$valuecount}.smw_sortkey";
}
$valuecount += 4;
} else {
$select .= ($select !== '' ? ',' : '') . "{$fieldname} AS v{$valuecount}";
}
$valuecount += 1;
}
if (!$issubject) {
// Apply sorting/string matching; only with given property
$where .= $this->store->getSQLConditions($requestoptions, $valueField, $labelField, $where !== '');
} else {
$valueField = '';
}
// *** Now execute the query and read the results ***//
$res = $db->select($from, $select, $where, 'SMW::getSemanticData', $usedistinct ? $this->store->getSQLOptions($requestoptions, $valueField) + array('DISTINCT') : $this->store->getSQLOptions($requestoptions, $valueField));
foreach ($res as $row) {
if ($issubject) {
// use joined or predefined property name
$propertykey = $proptable->isFixedPropertyTable() ? $proptable->getFixedProperty() : $row->prop;
}
// Use enclosing array only for results with many values:
if ($valuecount > 1) {
$valuekeys = array();
for ($i = 0; $i < $valuecount; $i += 1) {
// read the value fields from the current row
$fieldname = "v{$i}";
$valuekeys[] = $row->{$fieldname};
}
} else {
$valuekeys = $row->v0;
}
// Filter out any accidentally retrieved internal things (interwiki starts with ":"):
if ($valuecount < 3 || implode('', $fields) != 'p' || $valuekeys[2] === '' || $valuekeys[2][0] != ':') {
$result[] = $issubject ? array($propertykey, $valuekeys) : $valuekeys;
}
}
$db->freeResult($res);
wfProfileOut("SMWSQLStore3::fetchSemanticData-" . $proptable->getName() . " (SMW)");
return $result;
}
