Eloquent makes managing and working with these relationships easy, and supports a variety of common relationships:

One To One
A one-to-one relationship is a very basic type of database relationship. For example, a User model might be associated with one Phone model. To define this relationship, we will place a phone method on the User model. The phone method should call the hasOne method and return its result. The hasOne method is available to your model via the model's Illuminate\Database\Eloquent\Model base class:

class User extends Model
{
    /**
     * Get the phone associated with the user.
     */
    public function phone(): HasOne
    {
        return $this->hasOne(Phone::class);
    }
}
Dynamic properties allow you to access relationship methods as if they were properties defined on the model:
$phone = User::find(1)->phone;
If we would like the relationship to use a foreign key and primary key value other than id_user and id, we may pass a third argument to the hasOne method:
return $this->hasOne(Phone::class, 'foreign_key', 'local_key');
Next, let's define a relationship on the Phone model that will let us access the user that owns the phone. We can define the inverse of a hasOne relationship using the belongsTo method:
class Phone extends Model
{
    /**
     * Get the user that owns the phone.
     */
    public function user(): BelongsTo
    {
        return $this->belongsTo(User::class);
    }
}
A one-to-many relationship is used to define relationships where a single model is the parent to one or more child models. For example, a blog post may have an infinite number of comments. Like all other Eloquent relationships, one-to-many relationships are defined by defining a method on your Eloquent model:
class Post extends Model
{
    /**
     * Get the comments for the blog post.
     */
    public function comments(): HasMany
    {
        return $this->hasMany(Comment::class);
    }
}
Once the relationship method has been defined, we can access the collection of related comments by accessing the comments property. Remember, since Eloquent provides "dynamic relationship properties", we can access relationship methods as if they were defined as properties on the model:
$comments = Post::find(1)->comments;
foreach ($comments as $comment) {
    // ...
}
Since all relationships also serve as query builders, you may add further constraints to the relationship query by calling the comments method and continuing to chain conditions onto the query:
$comment = Post::find(1)->comments()
                    ->where('title', 'foo')
                    ->first();
Like the hasOne method, you may also override the foreign and local keys by passing additional arguments to the hasMany method:
return $this->hasMany(Comment::class, 'foreign_key');
return $this->hasMany(Comment::class, 'foreign_key', 'local_key');

To define the inverse of a hasMany relationship, define a relationship method on the child model which calls the belongsTo method:
class Comment extends Model
{
    /**
     * Get the post that owns the comment.
     */
    public function post(): BelongsTo
    {
        return $this->belongsTo(Post::class);
    }
}
An example of a many-to-many relationship is a user that has many roles and those roles are also shared by other users in the application. For example, a user may be assigned the role of "Author" and "Editor"; however, those roles may also be assigned to other users as well. So, a user has many roles and a role has many users. To define this relationship, three database tables are needed: users, roles, and role_user. role_user table is used as an intermediate table linking the users and roles. For example, let's define a roles method on our Usermodel:
class User extends Model
{
    /**
     * The roles that belong to the user.
     */
    public function roles(): BelongsToMany
    {
        return $this->belongsToMany(Role::class);
    }
}
Once the relationship is defined, you may access the user's roles using the roles dynamic relationship property:
use App\Models\User;
$user = User::find(1);
foreach ($user->roles as $role) {
    // ...
}
To define the "inverse" of a many-to-many relationship, you should define a method on the related model which also returns the result of the belongsToMany method. 
class Role extends Model
{
    /**
     * The users that belong to the role.
     */
    public function users(): BelongsToMany
    {
        return $this->belongsToMany(User::class);
    }
}
Eloquent provides some very helpful ways of interacting with the intermediate table. After accessing the relationship, we may access the intermediate table using the pivot attribute on the models:
$user = User::find(1);
foreach ($user->roles as $role) {
    echo $role->pivot->created_at;
}
By default, only the model keys will be present on the pivot model. If your intermediate table contains extra attributes, you must specify them when defining the relationship:
return $this->belongsToMany(Role::class)->withPivot('active', 'created_by');
If you would like your intermediate table to have created_at and updated_at timestamps that are automatically maintained by Eloquent, call the withTimestamps method when defining the relationship:
return $this->belongsToMany(Role::class)->withTimestamps();

Has One Through

The "has-one-through" relationship defines a one-to-one relationship with another model. However, this relationship indicates that the declaring model can be matched with one instance of another model by proceeding through a third model.
For example, in a vehicle repair shop application, each Mechanic model may be associated with one Car model, and each Car model may be associated with one Owner model. While the mechanic and the owner have no direct relationship within the database, the mechanic can access the owner through the Car model. Let's look at the tables necessary to define this relationship:

mechanics
    id - integer
    name - string
cars
    id - integer
    model - string
    mechanic_id - integer
owners
    id - integer
    name - string
    car_id - integer

The relationship on the Mechanic model:

class Mechanic extends Model
{
    /**
     * Get the car's owner.
     */
    public function carOwner(): HasOneThrough
    {
        return $this->hasOneThrough(Owner::class, Car::class);
    }
}

Has Many Through

The "has-many-through" relationship provides a convenient way to access distant relations via an intermediate relation. For example, let's assume we are building a deployment platform. A Project model might access many Deployment models through an intermediate Environment model. Using this example, you could easily gather all deployments for a given project. Let's look at the tables required to define this relationship:

projects
    id - integer
    name - string
environments
    id - integer
    project_id - integer
    name - string
deployments
    id - integer
    environment_id - integer
    commit_hash - string

The relationship on the Project model:

class Project extends Model
{
    /**
     * Get all of the deployments for the project.
     */
    public function deployments(): HasManyThrough
    {
        return $this->hasManyThrough(Deployment::class, Environment::class);
    }
}

The first argument passed to the hasManyThrough method is the name of the final model we wish to access, while the second argument is the name of the intermediate model.

Polymorphic Relationships

A polymorphic relationship allows the child model to belong to more than one type of model using a single association. For example, imagine you are building an application that allows users to share blog posts and videos. In such an application, a Comment model might belong to both the Post and Video models.

One To One (Polymorphic)

Table Structure
A one-to-one polymorphic relation is similar to a typical one-to-one relation; however, the child model can belong to more than one type of model using a single association. For example, a blog Post and a User may share a polymorphic relation to an Image model. Using a one-to-one polymorphic relation allows you to have a single table of unique images that may be associated with posts and users. First, let's examine the table structure:

posts
    id - integer
    name - string
 users 
   id - integer
    name - string
 images
    id - integer
    url - string
    imageable_id - integer
    imageable_type - string

Note the imageable_id and imageable_type columns on the images table. The imageable_id column will contain the ID value of the post or user, while the imageable_type column will contain the class name of the parent model. The imageable_type column is used by Eloquent to determine which "type" of parent model to return when accessing the imageable relation. In this case, the column would contain either App\Models\Post or App\Models\User.

<?php
 
namespace App\Models;
 
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\MorphTo;
 
class Image extends Model
{
    /**
     * Get the parent imageable model (user or post).
     */
    public function imageable(): MorphTo
    {
        return $this->morphTo();
    }
}
 
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\MorphOne;
 
class Post extends Model
{
    /**
     * Get the post's image.
     */
    public function image(): MorphOne
    {
        return $this->morphOne(Image::class, 'imageable');
    }
}
 
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\MorphOne;
 
class User extends Model
{
    /**
     * Get the user's image.
     */
    public function image(): MorphOne
    {
        return $this->morphOne(Image::class, 'imageable');
    }
}

Retrieving The Relationship

Once your database table and models are defined, you may access the relationships via your models. For example, to retrieve the image for a post, we can access the image dynamic relationship property:

use App\Models\Post;
$post = Post::find(1);
$image = $post->image;

You may retrieve the parent of the polymorphic model by accessing the name of the method that performs the call to morphTo. In this case, that is the imageable method on the Image model. So, we will access that method as a dynamic relationship property:

use App\Models\Image;
$image = Image::find(1);
$imageable = $image->imageable;

The imageable relation on the Image model will return either a Post or User instance, depending on which type of model owns the image.

One To Many (Polymorphic)

Table Structure

A one-to-many polymorphic relation is similar to a typical one-to-many relation; however, the child model can belong to more than one type of model using a single association. For example, imagine users of your application can "comment" on posts and videos. Using polymorphic relationships, you may use a single comments table to contain comments for both posts and videos. First, let's examine the table structure required to build this relationship:

posts
    id - integer
    title - string
    body - text
 videos
    id - integer
    title - string
    url - string
 comments
    id - integer
    body - text
    commentable_id - integer
    commentable_type - string

Model Structure

Next, let's examine the model definitions needed to build this relationship:

<?php
 
namespace App\Models;
 
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\MorphTo;
 
class Comment extends Model
{
    /**
     * Get the parent commentable model (post or video).
     */
    public function commentable(): MorphTo
    {
        return $this->morphTo();
    }
}
 
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\MorphMany;
 
class Post extends Model
{
    /**
     * Get all of the post's comments.
     */
    public function comments(): MorphMany
    {
        return $this->morphMany(Comment::class, 'commentable');
    }
}
 
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\MorphMany;
 
class Video extends Model
{
    /**
     * Get all of the video's comments.
     */
    public function comments(): MorphMany
    {
        return $this->morphMany(Comment::class, 'commentable');
    }
}
Retrieving The Relationship
Once your database table and models are defined, you may access the relationships via your model's dynamic relationship properties. For example, to access all of the comments for a post, we can use the comments dynamic property:

use App\Models\Post;
 
$post = Post::find(1);
 
foreach ($post->comments as $comment) {
    // ...
}
You may also retrieve the parent of a polymorphic child model by accessing the name of the method that performs the call to morphTo. In this case, that is the commentable method on the Comment model. So, we will access that method as a dynamic relationship property in order to access the comment's parent model:

use App\Models\Comment;
 
$comment = Comment::find(1);
 
$commentable = $comment->commentable;
The commentable relation on the Comment model will return either a Post or Video instance, depending on which type of model is the comment's parent.


Many-to-many polymorphic relations are slightly more complicated than "morph one" and "morph many" relationships. For example, a Post model and Video model could share a polymorphic relation to a Tag model. Using a many-to-many polymorphic relation in this situation would allow your application to have a single table of unique tags that may be associated with posts or videos. First, let's examine the table structure required to build this relationship:

posts
    id - integer
    name - string
videos
    id - integer
    name - string
tags
    id - integer
    name - string
taggables
    tag_id - integer
    taggable_id - integer
    taggable_type - string
Model Structure

Next, we're ready to define the relationships on the models. The Post and Video models will both contain a tags method that calls the morphToMany method provided by the base Eloquent model class.
The morphToMany method accepts the name of the related model as well as the "relationship name". Based on the name we assigned to our intermediate table name and the keys it contains, we will refer to the relationship as "taggable":

<?php
 namespace App\Models;
 use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\MorphToMany;
 class Post extends Model
{
    /**
     * Get all of the tags for the post.
     */
    public function tags(): MorphToMany
    {
        return $this->morphToMany(Tag::class, 'taggable');
    }
}
Defining The Inverse Of The Relationship
Next, on the Tag model, you should define a method for each of its possible parent models. So, in this example, we will define a posts method and a videos method. Both of these methods should return the result of the morphedByMany method.
The morphedByMany method accepts the name of the related model as well as the "relationship name". Based on the name we assigned to our intermediate table name and the keys it contains, we will refer to the relationship as "taggable":

<?php
 
namespace App\Models;
 
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\MorphToMany;
 
class Tag extends Model
{
    /**
     * Get all of the posts that are assigned this tag.
     */
    public function posts(): MorphToMany
    {
        return $this->morphedByMany(Post::class, 'taggable');
    }
 
    /**
     * Get all of the videos that are assigned this tag.
     */
    public function videos(): MorphToMany
    {
        return $this->morphedByMany(Video::class, 'taggable');
    }
}
Retrieving The Relationship
Once your database table and models are defined, you may access the relationships via your models. For example, to access all of the tags for a post, you may use the tags dynamic relationship property:

use App\Models\Post;
 
$post = Post::find(1);
 
foreach ($post->tags as $tag) {
    // ...
}

You may retrieve the parent of a polymorphic relation from the polymorphic child model by accessing the name of the method that performs the call to morphedByMany. In this case, that is the posts or videos methods on the Tag model:

use App\Models\Tag;
 
$tag = Tag::find(1);
 
foreach ($tag->posts as $post) {
    // ...
}
 
foreach ($tag->videos as $video) {
    // ...
}


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