Eloquent: Has Many Through Relationships - php

I am trying to figure out a relationship but I can't seem to solve the issue.
So what my script does first is checking if there is a valid session where status = 0.
Then I want to check if there is a valid trial where status = 0 ->first() associated with that session. And if so, I want to grab all the relevant data related by trial_id.
I understand what logic is required. However, I am wondering if there is a method to do this with as little commands as possible using Eloquent relationships.
Specifically, once i have the $session object. How can I filter the trials, in order to get the appropriate stimuli_tracker data?
The important components to the relationships for the table is as follows:
Sessions
id (has one to many relationship to trials(sessions_id)
user_id (foreign key)
status
Trials
id (one to many relationship with stimuli_tracker)
sessions_id (foreign key)
status
Stimuli_Tracker
trials_id (foreign key)
stimulus
stimulus_type
Sessions Model
class Sessions extends Model
{
protected $table = 'sessions';
public function stimuliTracker()
{
return $this->hasManyThrough('App\StimuliTracker', 'App\Trials', 'sessions_id','trials_id');
}
}
Trials Model:
class Trials extends Model
{
public function stimuli()
{
return $this->hasMany(App\StimuliTracker);
}
}
EDIT
I have tried in artisan tinker to
$object = \App\Session::where(arg);
then I tried to
$object->stimulus
but didn't work. I tried a few other fields but I only received null. Maybe I'm not getting how to grab the content properly

$object->stimulus is an undefined attribute based on what you've shown in your code.
To access the stimulus information for your session, you have to use the name of the relationship, which in this case is:
$object->stimuliTracker
The thing is that this will return an Eloquent Collection because it is a hasManyThrough relationship (which is a hasMany of a hasMany).
I'm assuming that the 'stimulus' attribute belongs to the StimuliTracker class. If this is the case, then you will need to loop through your StimuliTracker Collection to extract it:
foreach ( $object->stimuliTracker as $record )
{
$stimulus = $record->stimulus;
// do something with $stimulus
}
EDIT (Added):
If you are just looking for an array of the values in the 'stimulus' attribute, you can get that with the lists() method:
$stimulus_values = $object->stimuliTracker->lists('stimulus');

Related

Get name instead of ID one to one relationship

I have a make table and post table. Make table saves make names as make_code and make_name.
Post table has a column make. While saving a post, it will save make in make_code.
While displaying in blade, I want it to display as make_name. How can I do it?
Currently {{$post->make}} gives me make_code. I need it to show make_name.
I think its a one-to-one relationship that's needed. I tried putting it in model but did not work. How can I achieve it?
MAKE MODEL
class Make extends Model
{
public function make()
{
return $this->belongsTo(App\Post::class);
}
}
POST MODEL:
class Post extends Model
{
protected $table = 'posts';
}
Update
As Tim Lewis noticed:
the relationships can't be named make, as that's a conflict.
Assuming that the your relationship work like this:
a Make has many Post
a Post belongs to a Make object.
| Note: Correct me if I'm wrong.
So, if this is correct, you should define your relationships like this:
Post.php
public function make_rel()
{
return $this->belongsTo(Make::class, 'make', 'make_code');
}
Make.php
public function posts()
{
return $this->hasMany(Post::class, 'make', 'make_code');
}
Check the One-to-Many and One-to-Many (Inverse) relationship sections of the documentation.
So, you could do in your controller (or wherever you want):
$post = Post::find(1);
dd($post->make_rel->make_name); // 'Harley Davidson'
Additionally, you could create a computed property as a shorcout to access this related property in your Post model:
Post.php
// ...
public function getMakeNameAttribute()
{
return $this->make_rel->make_name;
}
Now, you can access it like this:
$post = Post::find(1);
dd($post->make_name); // 'Harley Davidson'
Suggestion
As a suggestion, I strongly advice you to change your foreign key column from make to make_id (in your 'posts' table) to avoid conflicts. Also, you could relate the post to the make primmary key instead of a custom key given the fact that this link is almost invisible and it is handled by Laravel. This would speed up the execution of the query because primmary id's are indexed by default.

Laravel 5.0 get the id of the row inserted in a pivot table after attach

I have a newsletter and block model that has a many to many relation. When I attach a block to a newsletter I want the id of the row that was insterted in the pivot table.
This is what I tried but results in "null"
$newsletter = Newsletter::findOrFail($newsletterId);
$newsletterBlock = $newsletter->blocks()->attach($blockId);
dd($newsletterBlock);
Although this question is old, however nobody gave the right answer. If you are in a situation that your pivot table has a primary key.
Using withPivot method is useful when you want get the id when you load the related model. However when you attach something you can not get the pivot_id;
In these situations best thing to do is to use a model that is connected to the pivot table, then only thing you need to do is inserting into pivot table using its model instead of attaching two models together.
in this example, first create a model called BlockNewsLetter if it is necessary fill the $table and $fillable attributes of the model and then you are good to go.
$newsletter = Newsletter::findOrFail($newsletterId);
$blockNewsLetterPivot = BlockNewsLetter::updateOrCreate([
'block_id' => $block_id ,
'newsLetter_id' => $newsletter->id
]);
$inserted_pivot_id = $blockNewsLetterPivot->id;
Try this, haven't test it but this should work:
/** Newsletter.php */
public function blocks()
{
return $this->belongsToMany('App\Block')
->withPivot('id');
}
Then in your controller:
$newsletter = Newsletter::findOrFail($newsletterId);
$newsletter->blocks()->attach($blockId);
// then you could:
foreach($newsletter->blocks as $block)
{
dd($block->pivot->id);
}
Check this section of the docs.

Laravel: get a model through another table

I have gotten a model called User. in this model i have a function called UserActivity where i return this:
return $this->hasMany('App\UserActivity', 'userid');
After this i have a function that gets the activity name from the Activity table, but i do not know how to do this, i have currently gotten this:
public function Activity() {
return $this->hasManyThrough('App\UserActivity', 'App\Activity', 'userid', 'activityid');
}
And in my view i want to use this like this:
$activiteiten = \App\User::find(Auth::user()->id);
dd($activiteiten->UserActivity()->Activity());
But then i get an error saying this:
Call to undefined method Illuminate\Database\Query\Builder::Activity() (View: /var/www/vhosts/cpned.nl/intranet.cpned.nl/laravel/resources/views/dashboard.blade.php)
I can do it using inner joins but i am really wondering if i can do this with Laravel models. I do not know how currently, and because i don't know what the name is for the function in laravel i can't find it either, so I am sorry if this will be a duplicate.
My tables have the following keys and foreign keys:
Users: pk: id
user_activities: pk: userid, activityid
activities: pk: id
Thank you in advance!
You can try using eager loading.
So something like:
$activiteiten = \App\User::with('UserActivity.Activity')->find(Auth::user()->id);
dd($activiteiten->UserActivity->Activity);
Edit: So then you can do something like this:
foreach($activiteiten->UserActivity as $user_activity) {
foreach($user_activity->Activity as $activity) {
print_r($activity);
}
}
Shows how you can loop through the relationships.
The Activity function should be in the User model. So then you can call it this way:
$activiteiten = \App\User::find(Auth::user()->id);
dd($activiteiten->Activity); //gives you a collection of activities
However, you need belongsToMany function rather than hasManyThrough since the relationship between users and activities is many-to-many.
This mean you cut down going through the Intermediate model. You can check the doc on belongsToMany to understand what to do better.
A side note: Why are your functions name starting with capital letter?
Also using hasMany relations should affect the function name as well, so that 'activity' becomes 'activities' (just to keep the functionality and interpretation in sync).
Update:
//User model
public function activities() {
return $this->belongsToMany('App\Activity', 'user_activity', 'userid', 'activityid');
}
This uses the 'user_activity' table, to find the relationship between users and activities, so that you may now access by User::first()->activities for example.

Laravel nested relationship not working

I have a user model which stores basic user information such as username, password etc.
There are also 3 types of user, Student, Staff and Parent. Each type also has a seperate model. For example, there is a Student model which belongs to a User model.
I also have a relationships table, which stores relationships between students and parents. This relationship is stored in the User model.
If I do something like:
App\Student::first()->user->relations;
It happily returns a collection of related parents.
In my Students model, I have a method called hasParent() which accepts a given user ID, and checks to ensure the student has a parent with that id. In that method, I have the following:
public function hasParent($parent)
{
return $this->user->relations->where('id', $parent)->count() === 1;
}
However, this returns an error Cannot call 'where' on a non-object. If I debug further, $this->user->relations returns an empty array.
The problem is, like above, if I call the methods separately, I get the results I want.
So to clarify, if I run:
App\Student::first()->user->relations;
This returns a collection of users just fine.
In my Student model however, if I call:
$this->user
Then I get the correct student
If I call
$this->user->relations
I get an empty array. Which doesn't make sense! Can anyone shed any light on this, or what I might be doing wrong? If you need any further info, please let me know.
You need to call where on the relation like below.
public function hasParent($parent)
{
return $this->user->relations()->where('id', $parent)->count() === 1;
}
See the parenthesis after the relations. If you call the relation without the parenthesis Laravel returns you a collection. To get the builder you need to call the relation with the parenthesis.
I'd suggest - to avoid creating a huge query overhead (which you'll do by calling where and count on the Query builder, not the collection) - to do what you're doing already, except using Illuminate Collections filter-method:
public function hasParent($parent)
{
return $this->user->relations->filter(function($relation) use ($parent){return $entity->id === $parent;})->count() === 1;
}

Eloquent where owner equals follow

I am trying to make a twitter like feed in an application, I have a database called connections where inside there's user and follow and another database called feed containing owner which would equal to the follow column in connections.
What I could do if had every id of a follower statically is to use where('owner', '=' $follow) on each follower and return it.
I tried this approach but it wasn't ideal:
Get each follower inside connections;
foreach(follower) {
Get 10 of the latest posts orderBy "created_at";
Push into array;
}
shuffle array;
limit array to 15;
return array;
That also ended with the returned array not being ordered by created date.
How would I use eloquent to get the feed item only if the user follows the owner in the best/simplest way?
Are there any specific Laravel tools that can be used?
Also the database layout isn't fixed as it is, it can be altered if needed to better suite this.
You need to create a many-to-many relationship between the user and itself. See the laravel eloquent documentation http://laravel.com/docs/eloquent#relationships. I didn't test this code but it should be enough to get you started down the right track.
Create a pivot table called "user_following" with:
(int) id, (int) user_id, (int) following_id
Then do something like this:
<?php
// Model
class User extends Eloquent {
public function following()
{
return $this->belongsToMany('User', 'user_following', 'user_id', 'following_id');
}
public function tweets()
{
return $this->hasMany('Tweet')->orderBy('created_at', 'desc');
}
}
// controller
$tweetsOfWhoImFollowing = User::find($id)->following->tweets;

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