Laravel有多对多关系？

Question

So I am using laravel and I am running into an issue, so I have relational model AdSale, then I have that setup with a hasOne relationship with AdImpressions. So for example say I grab all AdSale records where userId = 1. I get 5 different rows back, for each of those 5 rows I have 5 adImpression rows that match and have info about clicks and impressions. My end goal is to get the AdImpression rows. However when I run my has one Impressions() method I get undefined method. However If I do a foreach on my AdSale records individually and then run my Impresssions() method It works. So here is my code

class AdSale extends Eloquent{

     protected $table = 'AdSale';
     public function impressions()
     {
         return $this->hasOne('AdImpression','adSaleId','id');
     }

}

Here I am connecting my AdSale to its respective AdImpression via the adSaleId in the AdImpression table.

This is what I am running in my controller.

$sales= AdSale::where('userId','=', 1)->get();
$impressions = $sales->impressions();

Now what I expect from this is that my $impressions variable would have the AdImpressions entry that correlates to the adSaleId, however I am getting undefined function since there are multiple values returned to $saleLocation. If I change it to ->frist(); or do a foreach on $saleLocation it works but that will not work. I need to be able to total values from the impressions as a whole. Any info would be awesome.

Answer 1

I get 5 different rows back, for each of those 5 rows I have 5 adImpression rows that match and have info about clicks and impressions.

Based on that I assume that you're using the wrong relationship.

1. Change AdSale model relationship

return $this->hasMany('AdImpression','adSaleId');

2. Use eager loading :

$sales = AdSale::with('impressions')->where('userId', 1)->get();

3. Access as member, not method (relationship has already been loaded)

foreach($sales as $sale) {
    foreach($sale->impressions as $impression) {
        // 
    } 
}

4. Get sum of impressions

$sale->impressions->count()