private static function getSourceColumn(DbSchemaInfo $dbSchema, $sourceEntity, $targetEntity, $junctionTable)
{
$targetEntityMnReferences = $dbSchema->getEntityInfo($targetEntity)->mnReferences;
foreach ($targetEntityMnReferences as $reference => $referencedEntity) {
list($referencedTable, $referenceColumn) = explode(".", $reference);
if ($referencedTable === $junctionTable && $referencedEntity === $sourceEntity) {
return $referenceColumn;
}
}
return null;
}