public function unfollow($other)
{
// obtain the timestamps
$result = HypertableConnection::query("SELECT CELLS * FROM user WHERE " . "(CELL = '{$id}','following:{$other}' " . "OR CELL = '{$other}','followers:{$id}')");
$following_timestamp = $result->cells[0]->key->timestamp;
$followers_timestamp = $result->cells[1]->key->timestamp;
// DELETE following_history and followers_history
HypertableConnection::delete('user', $this->_id, 'following_history', $following_timestamp);
HypertableConnection::delete('user', $other, 'followers_history', $followers_timestamp);
// DELETE following and followers
HypertableConnection::delete('user', $this->_id, "following:{$other}");
HypertableConnection::delete('user', $other, 'followers:' . $this->_id);
// decrement the counters
HypertableConnection::insert('user', $this->_id, 'following_count', '-1');
HypertableConnection::insert('user', $other, 'followers_count', '-1');
}
