VersionPress\Database\VpidRepository::identifyEntity PHP Method

    public function identifyEntity($entityName, $data, $id)
    {
        if ($this->schemaInfo->getEntityInfo($entityName)->usesGeneratedVpids) {
            $data['vp_id'] = IdUtil::newId();
            $this->saveId($entityName, $id, $data['vp_id']);
            $data[$this->schemaInfo->getEntityInfo($entityName)->idColumnName] = $id;
        }
        $data = $this->fillId($entityName, $data, $id);
        return $data;
    }

 private function updateEntity($data, $entityName, $id)
 {
     $vpId = $this->vpidRepository->getVpidForEntity($entityName, $id);
     $data['vp_id'] = $vpId;
     if ($this->dbSchemaInfo->isChildEntity($entityName)) {
         $entityInfo = $this->dbSchemaInfo->getEntityInfo($entityName);
         $parentVpReference = "vp_" . $entityInfo->parentReference;
         if (!isset($data[$parentVpReference])) {
             $table = $this->dbSchemaInfo->getPrefixedTableName($entityName);
             $parentTable = $this->dbSchemaInfo->getTableName($entityInfo->references[$entityInfo->parentReference]);
             $vpidTable = $this->dbSchemaInfo->getPrefixedTableName('vp_id');
             $parentVpidSql = "SELECT HEX(vpid.vp_id) FROM {$table} t JOIN {$vpidTable} vpid ON t.{$entityInfo->parentReference} = vpid.id AND `table` = '{$parentTable}' WHERE {$entityInfo->idColumnName} = {$id}";
             $parentVpid = $this->database->get_var($parentVpidSql);
             $data[$parentVpReference] = $parentVpid;
         }
     }
     $shouldBeSaved = $this->mirror->shouldBeSaved($entityName, $data);
     if (!$shouldBeSaved) {
         return;
     }
     $savePostmeta = !$vpId && $entityName === 'post';
     // the post exists in DB for a while but until now it wasn't tracked, so we have to save its postmeta
     if (!$vpId) {
         $data = $this->vpidRepository->identifyEntity($entityName, $data, $id);
     }
     $this->mirror->save($entityName, $data);
     if (!$savePostmeta) {
         return;
     }
     $postmeta = $this->database->get_results("SELECT meta_id, meta_key, meta_value FROM {$this->database->postmeta} WHERE post_id = {$id}", ARRAY_A);
     foreach ($postmeta as $meta) {
         $meta['vp_post_id'] = $data['vp_id'];
         $meta = $this->vpidRepository->replaceForeignKeysWithReferences('postmeta', $meta);
         if (!$this->mirror->shouldBeSaved('postmeta', $meta)) {
             continue;
         }
         $meta = $this->vpidRepository->identifyEntity('postmeta', $meta, $meta['meta_id']);
         $this->mirror->save('postmeta', $meta);
     }
 }