lib/components/dataInterface/DataItem.php
public function getId()
    {
        if ($this->isForeign) {
            if (isset($this->foreignPrimaryKey)) {
                return $this->foreignPrimaryKey;
            } elseif (isset($this->foreignObject)) {
                return $this->foreignObject->primaryKey;
            }
        } else {
            if (isset($this->localPrimaryKey)) {
                return $this->localPrimaryKey;
            } elseif (isset($this->localObject)) {
                return $this->localObject->primaryKey;
            }
        }
        if (isset($this->primaryObject)) {
            return $this->primaryObject->primaryKey;
        }

        return;
    }
public function getId()
    {
        if ($this->isForeign) {
            if (isset($this->foreignPrimaryKey)) {
                return $this->foreignPrimaryKey;
            } elseif (isset($this->foreignObject)) {
                return $this->foreignObject->primaryKey;
            }
        } else {
            if (isset($this->localPrimaryKey)) {
                return $this->localPrimaryKey;
            } elseif (isset($this->localObject)) {
                return $this->localObject->primaryKey;
            }
        }
        if (isset($this->primaryObject)) {
            return $this->primaryObject->primaryKey;
        }

        return;
    }
Get id.

@return [[@doctodo return_type:getId]] [[@doctodo return_description:getId]]