Hello I am learning laravel and I am having an issue retrieving data from my relations.
In my database there are Product and Groups filled with dummy data.
I defined my relationship like this in product model:
public function Group()
{
return $this->hasMany('App\Groups','product_id', 'id');
}
And in my group vice versa with :
public function Product()
{
return $this->belongsTo('App\Product','product_id', 'id');
}
The way I am referencing to my products table is :
$table->foreign('product_id')->references('id')->on('products')->onDelete('cascade');
Now I have column product_id in my database under groups, and it is linked to if from products id it seems.
The groups table contains of its auto incremented id and product_id foreign key column.
While products table has auto incremented id and name column.
The issue is here : How do I return the products that are not null or have value (of products id) in groups table.
I tried something like this in my filter controller:
public function getProductsWithGroup()
{
$Products = Product::with('groups')->get();
return $Products ;
}
But that is giving me call to undefined relations.
I am not sure how to access belongsTo or hasMany methods and whether I need an extra group_id column in my products table.
You named the relationship wrong. It should be groups & define in lowercase as
public function groups()
{
return $this->hasMany('App\Groups','product_id', 'id');
}
And use ->has() to check existence
public function getProductsWithGroup()
{
$Products = Product::has('groups')->get();
return $Products ;
}
->with() is used to eager load and ->has() is used to check existence & filter.
To get the products don't have any groups,
$Products = Product::doesntHave('groups')->get();
To see other ways to use ->has() check, https://laravel.com/docs/5.7/eloquent-relationships#querying-relationship-existence
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