Nextras\Orm\Entity\Reflection\EntityMetadata::setPrimaryKey PHP Method

    public function setPrimaryKey(array $primaryKey)
    {
        $this->primaryKey = $primaryKey;
        return $this;
    }

 public function parseMetadata($class, &$fileDependencies)
 {
     $this->reflection = new ClassType($class);
     $this->metadata = new EntityMetadata($class);
     $this->primaryKey = [];
     $this->loadProperties($fileDependencies);
     $this->loadGettersSetters();
     // makes id property virtual on entities with composite primary key
     if ($this->primaryKey && $this->metadata->hasProperty('id')) {
         $this->metadata->getProperty('id')->isVirtual = TRUE;
     }
     $fileDependencies = array_unique($fileDependencies);
     $this->metadata->setPrimaryKey($this->primaryKey ?: ['id']);
     return $this->metadata;
 }