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Hi guys Im new to laravel, can someone explain to me the parameters of morphMany

$this->morphMany(Photo::class, 'imageable');

The MorphMany relationship has the following function signature:

public function morphMany($related, $name, $type = null, $id = null, $localKey = null)

 //

Where:

• 
  $related (required): refers to the related model. e.g: User::class
  


• 
  $name (required: the name of the polymorphic relation, like commentable
  


• 
  $type (optional): customize the relation_type field to look up when doing a query.


• 
  $id (optional): customize the relation_id field to look up when doing a query.


• 
  $localKey (optional): customize the local key (by default id) to search when doing a query.

So -using the example shown in the Laravel docuemntation- if you want to use a different table structure for the comments table from this:

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

to this:

posts
 id - integer
 title - string
 body - text

videos
 id - integer
 title - string
 url - string

comments
 id - integer
 body - text
 foo - integer // the index to look
 bar - string // the type to match

You'd need to define your relationships like this:

Post.php

public function comments()

 return $this->morphMany(Comment::class, 'commentable', 'foo', 'bar');

Video.php

public function comments()

 return $this->morphMany(Comment::class, 'commentable', 'foo', 'bar');

Comment.php

public function commentable()

 return $this->morphTo('commentable');

Check this other answer.

Polymorphic Relations

Table Structure

Polymorphic relations allow a model to belong to more than one other model on a single association. For example, imagine users of your application can "comment" on both posts and videos. Using polymorphic relationships, you can use a single comments table for both of these scenarios. 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

Two important columns to note are the commentable_id and commentable_type columns on the comments table. The commentable_id column will contain the ID value of the post or video, while the commentable_type column will contain the class name of the owning model. The commentable_type column is how the ORM determines which "type" of owning model to return when accessing the commentable relation.

Model Structure

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

<?php

namespace App;

use IlluminateDatabaseEloquentModel;

class Comment extends Model

 /**
 * Get all of the owning commentable models.
 */
 public function commentable()
 
 return $this->morphTo();
 


class Post extends Model

 /**
 * Get all of the post's comments.
 */
 public function comments()
 
 return $this->morphMany('AppComment', 'commentable');
 


class Video extends Model

 /**
 * Get all of the video's comments.
 */
 public function comments()
 
 return $this->morphMany('AppComment', 'commentable');
 

Retrieving Polymorphic Relations
Once your database table and models are defined, you may access the relationships via your models. For example, to access all of the comments for a post, we can use the comments dynamic property:

$post = AppPost::find(1);

foreach ($post->comments as $comment) 
 //

You may also retrieve the owner of a polymorphic relation from the polymorphic model by accessing the name of the method that performs the call to morphTo. In our case, that is the commentable method on the Comment model. So, we will access that method as a dynamic property:

$comment = AppComment::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 owns the comment.
See this link: polymorphic-relations:

You can entry like that:

+---------+----------------+-------------------+
| user_id | commentable_id | commentable_type |
+---------+----------------+-------------------+
| 1 | 1 | AppPost |
| 1 | 2 | AppPost |
| 1 | 3 | AppPost |
| 1 | 1 | AppVideo |
| 1 | 2 | AppVideo |
| 1 | 3 | AppVideo |
+---------+----------------+-------------------+