Relationship with the same table (Many to Many?) - Laravel - php

In my database I have to save people and the data of people that have a relationship with the first. For example: father, mother, son, daughter, etc
Then the design of the database, I did it in the following way Is a relation many-to-many because, a person have many people related to it.
But I'm not sure if is ok..
class Person extends Model
{
protected $fillable = [
'name',
'surname',
'profile_picture'
.....
];
public function relationships()
{
return $this -> belongsToMany(Person::class);
}
}
When I create the relation I create a thirth migration table call person_person to save the ids and a description (father, mother, son, daughter)
it's ok describe the relationship this way?
public function relationships()
{
return $this -> belongsToMany(Person::class);
}
What should I add to complete successful this relationship?

You'll need to define the table, primary and foreign key, as Laravel likely can't determine this (it'll try, but it probably won't succeed). Something like:
public function relationships(){
return $this->belongsToMany(Person::class, "person_person", "id_person", "id_person_related")
->withPivot(["parentesco"]);
}
or similar. Table name is a bit awkward, consider something else, like 'relationships' or something that conveys more meaning.
See https://laravel.com/docs/5.8/eloquent-relationships#many-to-many for details on how to define additional parameters for belongsToMany()

Laravel provide a nice convention for manyToMany relationship for two different tables but this convention does not work when we need manyToMany relationship in the same table.
solution steps:
create a pivot table and give it a meaningful name like relatives(person_person is not suitable)and create tow columns in this table persion_id and relative_persion_id.
with classname, pass other three arguments as the Table name (relatives), persion_id and relative_persion_id.
this link has perfect solutuion https://laracasts.com/series/laravel-6-from-scratch/episodes/58
public function relationships() { return $this->belongsToMany(Person::class,'relatives','persion_id','relative_persion_id'); }

Related

Laravel table relationship to pivot table

I'm confused on how to get my model setup in laravel with a table that is connected to a pivot table.
Here's the problem
Say I have
Locations
id
name
area_types
id
name
area_type_location (Pivot table)
id
location_id
area_type_id
area_test
id
area_type_location_id
clean
headCount
Relationship between the tables are different areas type belongs to different locations.
i.e: beach, 25m pools, kids pools, bbq, etc
area_test is connected to the pivot table because the test has to be generated from area that exists, in this case it is area that is registered under different locations. Thus it has to be tested daily, measured, etc.
I understand the structure between area_types and locations for many to many relationship, however I can't get over my head of how do i structure my area_test model? How do I get the data from locations table -> where are my test?
Should I create a model for my pivot table? Is that a good practice in laravel?
Does anyone has the same use case?
I read about eloquent has many through
relationship but I understand that it does not mention about getting through pivot table. I don't quite get if my use case is the same.
Thanks
Finally, apparently there are a couple of way to get data from locations table to area_tests
Tried at tinker and it works,
First Option
I need to create a Pivot model for my Pivot table:
class LocationAreaType extends Pivot{
public function location(){
return $this->belongsTo(Location::class);
}
public function areaType(){
return $this->belongsTo(AreaType::class);
}
public function AreaTests(){
return $this->hasMany(AreaTest::class, 'area_type_location_id');
}
}
I can use hasManyThrough relation that I need to create in my Location table
public function areaTests()
{
return $this->hasManyThrough(
AreaTest::class,
LocationAreaType::class,
'location_id',
'area_type_location_id');
}
this way I can get the areaTests easily by $location->areaTests, My problem was not determining the area_type_location_id as foreign. You need to determine this, apparently when I extends pivot and use hasMany laravel does not auto recognise the Foreign key by itself.
Second option
Another way to access it is from the relation table, I can define withPivot in the areaTypes() relation then access it like this:
$location->areaType[0]->pivot->areaTests
Since laravel only recognise foreign key from both tables location_id and area_type_id, I have to include the id of the pivot table to get the AreaTest table data
So in the Location model I have to get the column
public function areaTypes()
{
// Get the ID of the pivot table to get the poolTests table (connected with ID column)
return $this->belongsToMany(AreaType::class)
->using(AreaTypeLocation::class)
->withPivot('id');
}
There is no need to create a new model for pivot table.
Just declare in Location model below code:
/**
* #return \Illuminate\Database\Eloquent\Relations\BelongsToMany
*/
public function area_types()
{
return $this->belongsToMany('App\AreaType', 'area_type_location', 'location_id', 'area_type_id');
}
and declare below code in AreaType model:
/**
* #return \Illuminate\Database\Eloquent\Relations\BelongsToMany
*/
public function locations()
{
return $this->belongsToMany('App\Location', 'area_type_location', 'area_type_id', 'location_id');
}
every time you need to get for example the locations of an area_type in every controller, you can call the function like this: $areatype->locations()->get();
Don't forget to create area_type_location table migration.

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: 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.

How to assign relation when working with pivot table in Laravel 4?

Details
I have 3 tables :
catalog_downloads
export_frequencies
export_frequencies_catalog_downloads (Pivot Table)
Diagram
I am not sure if I set the relation between them correctly.
Please correct me if I am wrong.
Here is what I did
In CatalogDownload.php
public function export_frequencies(){
return $this->belongsToMany('ExportFrequency','export_frequencies_catalog_downloads','export_frequency_id','catalog_download_id');
}
In ExportFrequency.php
public function catalog_downloads(){
return $this->belongsToMany('CatalogDownload','export_frequencies_catalog_downloads','export_frequency_id','catalog_download_id');
}
Questions
According to my diagram - Did I assign the relationship correctly ?
I hope I didn't mix up between hasMany and belongsTo
Will I need a class or a model for a Pivot Table ?
Thanks
Since export_frequencies is in the CatalogDownload model you have to invert the ID's because the parameters of belongsToMany are as follows:
1. Name of the referenced (target) Model (ExportFrequency)
2. Name of the Pivot table
3. Name of the id colum of the referencing (local) Model (CatalogDownload in this case)
4. Name of the id colum of the referenced (target) Model (ExportFrequency in this case)
what leads to this function:
public function export_frequencies(){
return $this->belongsToMany('ExportFrequency','export_frequencies_catalog_downloads','export_frequency_id','catalog_download_id');
}
The other function was correct.
If you had some data in your pivot table, for instance a colum with the name someCounter then you will have to tell the relation to load that column when creating the pivot object like this:
public function export_frequencies(){
return $this->belongsToMany('ExportFrequency','export_frequencies_catalog_downloads','export_frequency_id','catalog_download_id')->withPivot('someCounter');
}
That will load the column and make it avalible like this:
$catalogDownload->export_frequencies()->first()->pivot->someCounter;
You will need a separate Pivot Model if you need to do some special handling for the fields or if that pivot itself has a relation of its own but then you might consider using a full blown model instead of a pure Pivot Model.
As an added note to the accepted answer, you are able to set up your many to many relationships without referencing the pivot table and the relevant id's as long as you follow a specific convention.
You can name your pivot table using singular references to the related tables, like 'catalog_download_export_frequency'. Notice the alphabetic order of the singular references.
Then you can simply do:
// CatalogDownload Model
public function exportFrequencies()
{
return $this->belongsToMany('ExportFrequency');
}
// ExportFrequency Model
public function catalogDownloads()
{
return $this->belongsToMany('CatalogDownload');
}
This will then allow you to run queries using the query builder or Eloquent like:
$catalogDownload->exportFrequencies()->get(); // Get all export frequencies for a specific CatalogDownload.
Or
$this->catalogDownload->with('exportFrequencies')->find($id); // Using eager loading and dependency injection, when CatalogDownload is assigned to $this->catalogDownload
Hope this helps!

Many to Many relationships with Laravel / Eloqeunt

I think I understand Eloquent for the most part, but I still have some trouble understanding many to many relationships.
I'm designing a sample database, and hopefully you folks can help me out understand the right way to do it.
Table 1: categories
cat_id
cat_name
Table 2: galleries
gallery_id
gallery_name
Table 3: galleryCategories
cat_id
gallery_id
So how would I go about my models? I found this topic, but it didn't seem quite right. maybe because it's a bit more complex relationship than what I need. I think the logic confused me because I'd expect products to have terms whereas terms having products in that example.
If you could please explain it with my sample, it'll help me better understand the belongsToMany() and hasMany() methods and their parameters. I'm also confused with some examples not taking any foreign key parameters.
Thanks already!
To make it work for your schema you need this:
// Category model
protected $primaryKey = 'cat_id';
public function galleries()
{
return $this->belongsToMany('Gallery', 'galleryCategories', 'gallery_id', 'cat_id');
}
// Gallery model
protected $primaryKey = 'gallery_id';
public function categories()
{
return $this->belongsToMany('Category', 'galleryCategories', 'cat_id', 'gallery_id');
}
// then:
$category = Category::first();
$category->galleries; // collection of Gallery models
To make it comply with Eloquent conventions, you would need:
// tables
categories: id, ...
galleries: id, ...
category_gallery: id, category_id, gallery_id [, timestamps]
// models
// Category
public function galleries()
{
return $this->belongsToMany('Gallery');
}
// Gallery
public function categories()
{
return $this->belongsToMany('Category');
}
The 2nd solution is way better if you want to make most of the framework, but if you want to rely on your schema, then you can make Eloquent adjust to it.
Note: hasMany is 1-m relation, belongsTo is its counterpart, while for many-to-many relationship with pivot table, you use belongsToMany on both ends.

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