public function setRelation($relation, $relationColumn = null)
    {
        $this->relation = $relation;
        $this->relationColumn = $relationColumn;

        return $this;
    }
public function setRelation($relation, $relationColumn = null)
    {
        $this->relation = $relation;
        $this->relationColumn = $relationColumn;

        return $this;
    }
public function setRelation ( $ relation , $ relationColumn = null ) { $ this -> relation = $ relation ; $ this -> relationColumn = $ relationColumn ; return $ this ; }
Set relation.

@param string $relation
@param string $relationColumn

@return $this
Set relation .