DSQL の orExpr() メソッドを使用して、必要に応じて SQL を生成できます。
例えば、
$m = $this->model->debug(); // enable debug mode
$user_id = $this->api->auth->model->id;// currently logged in user ID
$q = $m->_dsql(); // get models DSQL
$or = $q->orExpr(); // initialize OR DSQL object
$or->where('caller', $user_id) // where statements will be joined with OR
->where('callee', $user_id);
// use one of these below. see which one works better for you
$q->where($or); // add condition with OR statements
$q->having($or); // add condition with OR statements
もちろん、これらすべてを短く書くこともできます。
$m = $this->model->debug(); // enable debug mode
$user_id = $this->api->auth->model->id;// currently logged in user ID
$q = $m->_dsql(); // get models DSQL
$q->where($q->orExpr()
->where('caller', $user_id)
->where('callee', $user_id)
);