protected function optimizeRequiredField()
    {
        if (!array_key_exists('is-nullable', $this->meta) && !$this->field->isPrimary() && ($this->parser->isNullable() || !$this->parser->isRequired() || $this->parser->isConditionalRequired())) {
            $this->field->isNullable = true;
        }

        return $this;
    }