$query = "DELETE FROM
uploadsWHEREID= ' . $_POST['datensatzid'] . ' LIMIT 1" ;
falsche Anführungszeichen verwendet:
$query = 'DELETE FROM uploads WHERE ID = ' . $_POST['datensatzid'] . ' LIMIT 1 ;';
$query = "DELETE FROM
uploadsWHEREID= ' . $_POST['datensatzid'] . ' LIMIT 1" ;
falsche Anführungszeichen verwendet:
$query = 'DELETE FROM uploads WHERE ID = ' . $_POST['datensatzid'] . ' LIMIT 1 ;';