Has_Many and No Method Error Issue

Laravel hasMany method not working

The websites() function itself is not causing the error. The error is coming from wherever you are using the function.

The hasMany() function returns an Illuminate\Database\Eloquent\Relations\HasMany object. So, when you call $user->websites(), this will return the HasMany relationship object. Wherever you are using this function, you are then trying to convert that result to a string, which is the error you're seeing.

For example:

$user = User::find(1);
echo $user->websites();

In this example, if you try to echo the response from the websites() method, you will get the "could not be converted to string" error.

If this doesn't help you enough to resolve the issue, you will need to post the code that is calling the websites() function for anyone to be able to help further.

Edit

"The controller doesn't echo the websites() method, it just returns it." Anything returned by a controller method is converted to a string. This is your issue.

Instead of returning the HasMany object, you need to return the results of the HasMany object. There are two main options: call get() on the relationship to actually get the results and return that, or use the relationship attribute instead of the method.

Option 1:

public function show() {
    $user = User::find(5);

    // call "get()" to get the results
    return $user->websites()->get();
}

Option 2:

public function show() {
    $user = User::find(5);

    // use lazy loaded attribute instead of using relationship method
    return $user->websites;
}

Both of the options above will return the same thing: a Collection of the Website objects. Since you're returning this from the controller, Laravel will convert this to a string, so your output will be a json array of json Website objects.

Laravel Eloquent relationships hasmany error: Call to undefined method when using on where

It should be.You can use with method load relationship data

return Workspace::where('user_id', '=', 1)->with('projects')->get();

For better understanding with accept two params

 with($relations, $callback = null)

callbacks help us to write query on relations

with Set the relationships that should be eager loaded.

Laravel attach() method not working to hasMany side

See the Laravel documentation here:
http://laravel.com/docs/eloquent#inserting-related-models

Basically you have set up two different types of relationships for the same two tables - you've set up a many-to-many and a one-to-many. It looks as though you probably wanted a many-to-many, so you'll need to change this line:

return $this->hasMany('Atividade');

To this:

return $this->belongsToMany('Atividade');

This will set the relationship up as a many-to-many relationship, which will then support the attach() method.

The attach() method is only for many-to-many, for other relationships there's save() or saveMany() and associate() (see the docs linked above).

Laravel relationship hasMany not working

First change your relationship

Inventory.php

public function user(){
    return $this->belongsTo("App\User", 'finished_by');
}

User.php

public function inventories(){
    return $this->hasMany("App\Inventory", 'finished_by');
}

You need to add user relationship in eager loading

$inventories = Inventory::where('company_id',$company_id)->with('user')->get();

Now Template Rendering

@foreach($inventories as $inventory)
    <tr>
        <td>{{$inventory->id}}</td>
        <td>
           @if($inventory->user)
              {{$inventory->user->name}}
           @else
              'No User'
           @endif
        </td>   
    </tr>
@enforeach

has_many :through association, No Method Error in rails console in shell, NoMethodError: undefined method for #ActiveRecord::Relation:

Your first problem is easy to solve: Please note that where does not return one single object from the database, even if there was only one entry found. where returns an ActiveRecord::Relation, that acts as a list in the context of your question.

Box.where("id" => 2)
#=> [#<Box id: 2, ... # Note the `[` at the beginning of the line

And you cannot call products on this Relation, because products is defined on Box, but not on Relation.

You can fix this problem in different ways depending on your needs.

You could iterate and over that list and call products on each entry:

Box.where(id: 2).map(&:products)
Box.where(id: 2).includes(:products)

Or your could use a method that only returns a single element:

Box.find(2).products
Box.find_by(id: 2).products
Box.where(id: 2).take.products
Box.where(id: 2).first.products

Laravel Call to undefined method HasMany::mapInto() when requesting data

When You are Calling user()->partners() it returns Illuminate\Database\Eloquent\Relations\HasMany Instance.

Resource needs to get Illuminate\Database\Eloquent\Collection Instance.

You have to just call user()->partners ( Remove parenthesis )

Or call get method on Illuminate\Database\Eloquent\Relations\HasMany Instance, to get Collection

user()->partners()->get()

NoMethodError, has_many and belongs_to association

The problem is that you are calling the contents method on a collection of articles.

Try this:

<div class="col-md-6" style="background:yellow;"><%= @user.articles.map(&:contents).join(', ') %></div>

Rails - has_many relation causes NoMethodError

As it turns out, the problem is the database field platform_id. This messes up rails. Simply delete it and it'll work.

has_many :through Association, NoMethodError (undefined method `each' for :String) and save association

I figured out a right solution for me with this answer and this question.

First solution to just save one Post::Category with a Post

Regarding to this answer, I had to change my permit parameter in the posts_controller to this:

def post_params
  params.require(:post).permit(:post_category_ids)
end

Then I need also to change the select in the view where I create a post with a post_category to this:

<div class="form-group">
  <%= f.label :post_category_ids, :class => 'control-label', :value => 'Category: ' %>
  <%= f.select :post_category_ids, options_from_collection_for_select(all_post_categories, :id, :name), {}, {class: 'selectpicker', :'data-live-search' => 'true', required: 'false' } %>
</div>

That's it. The rest of the code is still the same as I showed before my second try in my question.

Second solution to save multiple Post::Category with a Post

Regarding to this question, I need to change my permit parameter in the posts_controller to this:

def post_params
  params.require(:post).permit(:post_category_ids => [])
end

And to select more than one Post::Category at the same time, I need to add multiple: 'true' to the select in the view:

<div class="form-group">
  <%= f.label :post_category_ids, :class => 'control-label', :value => 'Category: ' %>
  <%= f.select :post_category_ids, options_from_collection_for_select(all_post_categories, :id, :name), {}, {class: 'selectpicker', :'data-live-search' => 'true', required: 'false', multiple: 'true' } %>
</div>

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