I have three tables categories, film_categories and films and three models respectively Category, FilmCategory and Film.
I have seen many tutorials where they don't create a pivot table model like i have created FilmCategory Model . They just create a pivot table film_categories without a model.
My question is what is the best practise - ?
Should i create a FilmCategory model and set a hasMany relationship
class Film extends Model
{
use HasFactory;
protected $primaryKey = 'film_id';
/**
* Film film Relationship
*
* #return Illuminate\Database\Eloquent\Relations\HasMany
*/
public function categories()
{
return $this->hasMany(FilmCategory::class, 'film_id', 'film_id');
}
}
OR
Should i just create a pivot table film_categories without a model FilmCategory and set belongsToMany relationship
class Film extends Model
{
use HasFactory;
protected $primaryKey = 'film_id';
/**
* Film film Relationship
*
* #return Illuminate\Database\Eloquent\Relations\HasMany
*/
public function categoriesWithPivot()
{
return $this->belongsToMany(Category::class, 'film_categories', 'film_id', 'category_id');
}
}
Technically speaking, both option are fine. You can implement the two of them, and depends on what you want to implement/achieve in the logic part of the code, use one between the two that suits best. Here are things to consider:
First, depends on what is film_categories table used for. If the table is simply exists to relate films and categories tables using many-to-many relationship, then there's no need to create the FilmCategory model, and you can just use belongsToMany(). Otherwise, if the film_categories will relates to another table, then you should create FilmCategory model and define the relation using hasMany(). You're also likely need to add a primary-key field to film_categories if this is the case.
The second consideration to take is what kind of data structure you want to have. Using the codes that you provide, you can get Films using these 2 queries and it'll gives you the correct values but with different structures:
Film::with('categoriesWithPivot')->get();
// Each record will have `Film`, `Category`, and its pivot of `film_categories` table
// OR
// Assuming that `FilmCategory` model has `belongsTo` relation to `Category` ...
Film::with('categories', 'categories.category')->get();
// Will gives you the same content-values as the above, but with in a different structure
And that's it. The first point is mostly more important to consider than the second. But the choice is completely yours. I hope this helps.
Since the film_categories table does not represent an entity in your system, I think you should define a belongsToMany relationship and should not create a separate model for the pivot table. If You still wanna have a model for your pivot table so create a model that extends Illuminate\Database\Eloquent\Relations\Pivot class. Check documentation here: model for pivot table
Related
I've the following tables:
1.institute_codes
id
institute_id
course_id
code
1
3
45
ABCD
2.code_claims
id
code_id
user_id
approved
1
1
4
0
The institute_codes and code_claims are pivot tables. I want to retrieve users details based on the user_id column in code_claims and the course information which corresponds to the used code(code_id in code_claims table).
I've the following relationships till now:
class InstituteCode extends Pivot
{
use HasFactory;
protected $table = ['institute_codes'];
public function users()
{
return $this->belongsToMany(User::class, 'code_claims', 'code_id');
}
}
class User extends Model
{
public function codes()
{
return $this->belongsToMany(InstituteCode::class, 'code_claims');
}
}
Any help would be appreciated. Thanks.
So what exactly is your question here? :)
Your relationships are all messed up. I would read into the Laravel documentation first on relationships.
A basic has many / belongs to relationship is important, but also this one might be very interesting in your situation:
https://laravel.com/docs/9.x/eloquent-relationships#has-many-through
Also take note of the foreign key conventions below it.
One important tip is that the BelongsTo relation should always go in the model of the table with the foreign key (f.e. user_id). This way you can not go wrong.
I would like to obtain for ONE user his country. So I have two tables:
User
id
country_id
Countries
id
I can't decide which relationship to use. I think it is the OneToMany relationship (Inverse) but it implies that the Countries table has the user id.
I can't understand how to use the oneToMany relationship in this case...
Docs link: https://laravel.com/docs/6.x/eloquent-relationships#one-to-many-inverse
One To Many (Inverse)
Now that we can access all of a post's comments, let's define a relationship to allow a comment to access its parent post. To define the inverse of a hasMany relationship, define a relationship function on the child model which calls the belongsTo method:
You need to create a belongsTo to relation on your user model.
class User extends Model
{
public function country()
{
return $this->belongsTo('App\Country');
}
}
My Setup
I have a many-to-many relationship setup and working with my database. This is using a pivot table that has an extra column named "linked_by". The idea of this is that I can track the user that created the link between the other 2 tables.
Below is an attempted visual representation:
permissions -> permissions_roles -> roles
permissions_roles -> persons
The Issue
The permissions_roles table has an addition column names "linked_by" and I can use the ->pivot method to get the value of this column. The issue is that it only returns the exact column value. I have defined a foreign key constraint for this linked to persons.id but I can't manage to work out a way to query this from a laravel Eloquent model.
The Question
How do I query the name of the person linked to the "linked_by" column form the Eloquent query?
Ideally, I would like the query to be something like:
permissions::find(1)->roles->first()->pivot->linked_by->name;
BUT, as I haven't defined an eloquent relationship for this pivot table column I can't do this but I can't work out how I would do this if it is even possible?
Is the only way to do this to do:
$linkee = permissions::find(1)->roles->first()->pivot->linked_by;
$person = person::find($linkee);
$person->name;
->using();
I have discovered that Laravel has a way to do what I wanted out of the box by creating a model for the pivot table.
This works by adding ->using() to the return $this->belongsToMany() model function.
By putting the name of the newly created pivot model inside the ->using() method, we can then call any of the functions inside this pivot model just like any other eloquent call.
So assuming that my permissions belongs to many roles and the pivot table has a 3rd column named "linked_by" (which is a foreign key of a user in the Users table):
My permissions model would have:
public function roles()
{
return $this->belongsToMany('App\roles','permissions_roles','permissions_id','roles_id')
->using('App\link')
->withPivot('linked_by');
}
and the new link model would contain:
Notice the extends pivot and NOT model
use Illuminate\Database\Eloquent\Relations\Pivot;
class link extends Pivot
{
//
protected $table = 'permissions_roles';
public function linkedBy()
{
return $this->belongsTo('App\users', 'linked_by');
}
}
Obviously you would need to define the opposite side of the belongsToMany relationship in the roles model, but once this is done I can use the following to pull the name of the person that is linked to the first role in the linked_by column:
permissions::find(1)->roles->first()->pivot->linked_by->name;
You should be able to achieve that in toArray method in Permission model.
/**
* Convert the model instance to an array.
*
* #return array
*/
public function toArray(): array
{
$attributes = $this->attributesToArray();
$attributes = array_merge($attributes, $this->relationsToArray());
// Detect if there is a pivot value and return that as the default value
if (isset($attributes['pivot']['linked_by']) && is_int($attributes['pivot']['linked_by'])) {
$linkeeId = $attributes['pivot']['linked_by'];
$attributes['pivot']['linkee'] = Person::find($linkeeId)->toArray();
//unset($attributes['pivot']['linked_by']);
}
return $attributes;
}
I am looking over some laravel code and I have a few questions regarding the code. In the view, I see a piece of code "$data->profile->age". Does this code automatically find the profile record in the profile table associated with the $data? How does it find the associated profile?
Controller:
return view('new-design.pages.influencer.info')
->withData($data)
View:
$data->profile->age
Yes. It finds the associated profile using the relations you definied in your Profile model
Once the relationship is defined, we may retrieve the related record using Eloquent's dynamic properties. Dynamic properties allow you to access relationship methods as if they were properties defined on the model:
Here's a simple example from the documentation to help you understand:
Let's say you have a posts table and a comments table:
We need to define a relationship between this two tables.
A one-to-many relationship is used to define relationships where a single model owns any amount of other models. For example, a blog post may have an infinite number of comments.
Note: you must have a foreign key in your comments table referencing the posts table, like post_id, in this case, if you use a different name you should inform that in your relation:
Remember, Eloquent will automatically determine the proper foreign key column on the Comment model. By convention, Eloquent will take the "snake case" name of the owning model and suffix it with _id. So, for this example, Eloquent will assume the foreign key on the Comment model is post_id.
In your Post model you could do:
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Post extends Model
{
/**
* Get the comments for the blog post.
*/
public function comments()
{
return $this->hasMany('App\Comment');
}
}
And in your Comment model you should define the inverse relationship
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Comment extends Model
{
/**
* Get the post that owns the comment.
*/
public function post()
{
return $this->belongsTo('App\Post');
}
}
Now, if you want to access all comments from a post you just need to get the relation:
$post = Post::find($id); // find a post
$post->comments; // This will return all comments that belong to the given post
So, you basically access them as if they were a property from the model, as said in the documentation
In your view you could do something like this:
#foreach($post->comments as $comment)
{
{{$comment->text}}
}
#endforeach
This example will print every comment text from the Post we get in the controller.
I reckon in your model for $data there is a function called profile. From that it is getting the equivalent profile.
Example: Imagine you have a model called phone and you want to find the user who owns it. You can write the following function in your model.
public function user()
{
return $this->belongsTo('App\User');
}
And in the view you may write something like
$phone->user->name
Now, behind the scene laravel will go to the phone and get the value from user_id for that phone. (If the foreign key is located in different column you can specify that too). Then laravel will find the users table with that user_id and retrieve the row. Then show the name on view.
Now if there is a complex query you can also write a function for that in the model.
I am curious about how eloquent knows in which table it should save the records we give it by running $ php artisan tinker . I do not actually remember setting so an option.
In Laravel when using Eloquent you should assign a table name using the property $table for example:
protected $table = 'some_thing';
Otherwise it assumes that the table name is the plural form of the model name and in this case for User model the table name should be users. Follwing paragraph is taken from Laravel website:
Table Names
Note that we did not tell Eloquent which table to use for our Flight
model. The "snake case", plural name of the class will be used as the
table name unless another name is explicitly specified. So, in this
case, Eloquent will assume the Flight model stores records in the
flights table.
// You may use this instead:
class Flight extends Model
{
// Explicit table name example
protected $table = 'my_flights';
}
So, if you don't follw this convention when creating/naming your database tables that Laravel expects then you have to tell Laravel the name of the table for a model using a protected $table property in your model.
Read the documentation here.
Actually if you not set the $table property, Eloquent will automatically look the snake case and plural name of the class name. For example if class name is User, it will users.
Here the code taken from Illuminate/Database/Eloquent/Model.php
public function getTable()
{
if (isset($this->table)) {
return $this->table;
}
return str_replace('\\', '', Str::snake(Str::plural(class_basename($this))));
}
Model name is mapped to the plural of table name, like User model maps to users table and so.
When you do
User::all() laravel knows that you want the records from users table.
To specify the table name explicitly you use protected $table ='name' field on model.
Actually, Eloquent in its default way, is an Active Record System just like Ruby On Rails has. Here Eloquent is extended by a model. Those model name can be anything starts with capital letter. Like for example User or Stock
but the funny thing is this active record system will imagine that if no other name of custom table is specified within the class model then the table name should be the small cased plural form of the Model name. In these cases users and stocks.
But by keeping aside theses names you can extensively can provide your own table name within the model. As in Laravel protected $table= 'customTableName'
Or, in a more descriptive way,
class Stock extends Eloquent{
// Custom Table Name
protected $table = 'custom_tables';
}
I hope this will solve your curious mind.