silverstripe-framework/src/ORM/ManyManyThroughQueryManipulator.php

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<?php
namespace SilverStripe\ORM;
use SilverStripe\Core\Injector\Injectable;
use SilverStripe\Core\Injector\Injector;
use SilverStripe\ORM\Queries\SQLSelect;
/**
* Injected into DataQuery to augment getFinalisedQuery() with a join table
*/
class ManyManyThroughQueryManipulator implements DataQueryManipulator
{
use Injectable;
/**
* DataObject that backs the joining table
*
* @var string
*/
protected $joinClass;
/**
* Key that joins to the data class
*
* @var string $localKey
*/
protected $localKey;
/**
* Key that joins to the parent class
*
* @var string $foreignKey
*/
protected $foreignKey;
/**
* Build query manipulator for a given join table. Additional parameters (foreign key, etc)
* will be infered at evaluation from query parameters set via the ManyManyThroughList
*
* @param string $joinClass Class name of the joined dataobject record
* @param string $localKey The key in the join table that maps to the dataClass' PK.
* @param string $foreignKey The key in the join table that maps to joined class' PK.
*/
public function __construct($joinClass, $localKey, $foreignKey)
{
$this->setJoinClass($joinClass);
$this->setLocalKey($localKey);
$this->setForeignKey($foreignKey);
}
/**
* @return string
*/
public function getJoinClass()
{
return $this->joinClass;
}
/**
* @param mixed $joinClass
* @return $this
*/
public function setJoinClass($joinClass)
{
$this->joinClass = $joinClass;
return $this;
}
/**
* @return string
*/
public function getLocalKey()
{
return $this->localKey;
}
/**
* @param string $localKey
* @return $this
*/
public function setLocalKey($localKey)
{
$this->localKey = $localKey;
return $this;
}
/**
* @return string
*/
public function getForeignKey()
{
return $this->foreignKey;
}
/**
* @param string $foreignKey
* @return $this
*/
public function setForeignKey($foreignKey)
{
$this->foreignKey = $foreignKey;
return $this;
}
/**
* Get has_many relationship between parent and join table (for a given DataQuery)
*
* @param DataQuery $query
* @return HasManyList
*/
public function getParentRelationship(DataQuery $query) {
// Create has_many
$list = HasManyList::create($this->getJoinClass(), $this->getForeignKey());
$list = $list->setDataQueryParam($this->extractInheritableQueryParameters($query));
// Limit to given foreign key
if ($foreignID = $query->getQueryParam('Foreign.ID')) {
$list = $list->forForeignID($foreignID);
}
return $list;
}
/**
* Calculate the query parameters that should be inherited from the base many_many
* to the nested has_many list.
*
* @param DataQuery $query
* @return mixed
*/
public function extractInheritableQueryParameters(DataQuery $query) {
$params = $query->getQueryParams();
// Remove `Foreign.` query parameters for created objects,
// as this would interfere with relations on those objects.
foreach(array_keys($params) as $key) {
if(stripos($key, 'Foreign.') === 0) {
unset($params[$key]);
}
}
// Get inheritable parameters from an instance of the base query dataclass
$inst = Injector::inst()->create($query->dataClass());
$inst->setSourceQueryParams($params);
return $inst->getInheritableQueryParams();
}
/**
* Get name of join table alias for use in queries.
*
* @return string
*/
public function getJoinAlias() {
return DataObject::getSchema()->tableName($this->getJoinClass());
}
/**
* Invoked prior to getFinalisedQuery()
*
* @param DataQuery $dataQuery
* @param array $queriedColumns
* @param SQLSelect $sqlSelect
*/
public function beforeGetFinalisedQuery(DataQuery $dataQuery, $queriedColumns = [], SQLSelect $sqlSelect)
{
// Get metadata and SQL from join table
$hasManyRelation = $this->getParentRelationship($dataQuery);
$joinTableSQLSelect = $hasManyRelation->dataQuery()->query();
$joinTableSQL = $joinTableSQLSelect->sql($joinTableParameters);
$joinTableColumns = array_keys($joinTableSQLSelect->getSelect()); // Get aliases (keys) only
$joinTableAlias = $this->getJoinAlias();
// Get fields to join on
$localKey = $this->getLocalKey();
$schema = DataObject::getSchema();
$baseTable = $schema->baseDataClass($dataQuery->dataClass());
$childField = $schema->sqlColumnForField($baseTable, 'ID');
// Add select fields
foreach($joinTableColumns as $joinTableColumn) {
$sqlSelect->selectField(
"\"{$joinTableAlias}\".\"{$joinTableColumn}\"",
"{$joinTableAlias}_{$joinTableColumn}"
);
}
// Apply join and record sql for later insertion (at end of replacements)
$sqlSelect->addInnerJoin(
'(SELECT $$_SUBQUERY_$$)',
"\"{$joinTableAlias}\".\"{$localKey}\" = {$childField}",
$joinTableAlias,
20,
$joinTableParameters
);
$dataQuery->setQueryParam('Foreign.JoinTableSQL', $joinTableSQL);
// After this join, and prior to afterGetFinalisedQuery, $sqlSelect will be populated with the
// necessary sql rewrites (versioned, etc) that effect the base table.
// By using a placeholder for the subquery we can protect the subquery (already rewritten)
// from being re-written a second time. However we DO want the join predicate (above) to be rewritten.
// See http://php.net/manual/en/function.str-replace.php#refsect1-function.str-replace-notes
// for the reason we only add the final substitution at the end of getFinalisedQuery()
}
/**
* Invoked after getFinalisedQuery()
*
* @param DataQuery $dataQuery
* @param array $queriedColumns
* @param SQLSelect $sqlQuery
*/
public function afterGetFinalisedQuery(DataQuery $dataQuery, $queriedColumns = [], SQLSelect $sqlQuery)
{
// Inject final replacement after manipulation has been performed on the base dataquery
$joinTableSQL = $dataQuery->getQueryParam('Foreign.JoinTableSQL');
if ($joinTableSQL) {
$sqlQuery->replaceText('SELECT $$_SUBQUERY_$$', $joinTableSQL);
$dataQuery->setQueryParam('Foreign.JoinTableSQL', null);
}
}
}