...
<global>
<models>
<myarticles>
<class>My_Articles_Model</class>
<resourceModel>myarticles_resource</resourceModel>
</myarticles>
<myarticles_resource>
<class>My_Articles_Model_Resource</class>
<entities>
<article>
<table>myarticles</table>
</article>
</entities>
</myarticles_resource>
</models>
...
</global>
$pdo->fetchAll(PDO::FETCH_COLUMN|PDO::FETCH_GROUP)