Virtual Host redirect for non existen subdomains to www

I know there are a number of different ways to redirect using apache although I wanted to check if this is the correct way of doing it via virtual host?

<VirtualHost *:80>
ServerName example.com
ServerAlias www.example.com
DocumentRoot /var/www/example/public

<Directory "/var/www/example/public">
    Options +FollowSymlinks

    # Prevent Direct Access to files
    <FilesMatch "\.(tpl|ini|log)">
     Order deny,allow
     Deny from all
    </FilesMatch>

    RewriteEngine On
    RewriteBase /
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule ^([^?]*) index.php?_route_=$1 [L,QSA]
</Directory>

<Directory "/var/www/example/public/admin/view/javascript/ckeditor">
        AddType application/x-javascript .js
        AddType text/css .css
        AddType text/xml .xml
    </Directory>

    ErrorLog /var/log/apache2/example-error.log
    LogLevel warn
    CustomLog /var/log/apache2/example-access.log combined
</VirtualHost>

    # Redirect for all non existent subdomains
    <VirtualHost *:80>
        ServerAlias *.example.com
        Redirect 301 / http://www.example.com
    </VirtualHost>