Hum,

Maybe something like this ..

public function children()
    {
        return $this->hasMany('App\Child', 'my_model_id', 'id')->where('child.data', 1);
    }

You lose the attribute value but since it is the same as the child->data you still have the value, just with a different key.

I'm not 100% on the where statement, but I think i did something similar somewhere, but... not enough caffeine yet today.

That's an interesting thought with the dot notation, I forget you can do that.

That's good for filtering but I do want to return all the child models even if child.data != 1, and then calculate the attribute based on the child.data values as a whole. I guess that's where my situation gets a bit tricky.

For example, if any of child.data = 1, i want MyModel->attribute = 1. If all of child.data = 0, MyModel->attribute = 0

I ended up fetching all the results first, then looping through the Child collection, extracting a result, then merging the attribute manually into the collection.

I guess I'm thinking it would be nice if the getModelStatusAttribute could "share" the data returned from the ->children() method. But that seems to be resolved AFTER the model attributes are set...

NOTE: I changed getChildStatusAttribute to getModelStatusAttribute, to reflect more clearly what I'm aiming for

Humm..

What about using $this->children in the getModelStatusAttribute function instead of calling Child again?

Also, the attribute value is set to 1 when the first child with a data is equal to 1, not sure about the continued looping over the children since it never changes.

Here are the code notes,

public function children()
    {
        return $this->hasMany('App\Child', 'my_model_id', 'id');
    }

 public function getModelStatusAttribute()
    {
        /* inefficient - the children() method already
           causes the query builder to lookup children */
       // $children = Child::where('my_model_id', $this->id)->get();
        // Perhaps changing this to ...
        $children = $this->children(); // with the change to the children function to include the my_model_id relationship

        $attribute = 0;

        foreach($children as $child) {
            if ($child->data == 1) {
                $attribute = 1;  // <== it is one from this point, for every child past
                break;  // ?? maybe since no need to continue looping the children
            }
        }

        return $attribute;
    }