The record of the Laravel morphToMany association table is incorrect when it is saved.

attachment (Attachment) can be used as either a picture of the comment details (CommentDetail) or an avatar of the user"s (User). Their data structures are as follows:

CommentDetail
    id - integer
    cid - integer
    content - text
User
    id - integer
    name - string
Attachment
    id - integer
    key - string
AttachmentRelationship
    id - integer
    target_type - string ("comment_detail" or "user_avatar")
    target_id - integer (User -> id or CommentDetail -> cid)
    attachment_key - string

first of all, I defined morphMap: in AppServiceProvider

Relation::morphMap([
    "comment_detail" => CommentDetail::class,
    "user_avatar" => User::class,
]);

then, in the CommentDetail model, define the method to get all attachments:

public function attachments()
{
    return $this->morphToMany(
        Attachment::class,
        "target",
        "attachment_relationships", 
        "target_id",
        "attachment_key",
        "cid",
        "key"
    );
}

finally, add attachments and associated data to a commentDetail:

$commentDetail = CommentDetail::findOrFail(4);
$attachment = $commentDetail->attachments()->create([
    "key" => (string)\Uuid::uuid4(),
]);

the record created in the table corresponding to Attachment is:

< table > < thead > < tr > < th > id < / th > < th > key < / th > < / tr > < / thead > < tbody > < tr > < td > 10 < / td > < td > 968e22b8-e4fb-4743-bf08-8ac9cd8ecd56 < / td > < / tr > < / tbody > < / table >

the record in the AttachmentRelationship corresponding table is:

< table > < thead > < tr > < th > id < / th > < th > target_type < / th > < th > target_id < / th > < th > attachment_key < / th > < / tr > < / thead > < tbody > < tr > < td > 1 < / td > < td > comment_detail < / td > < td > 7 < / td > < td > 10 < / td > < / tr > < / tbody > < / table >

my question is: why is the value of the attachment_key field of this record in AttachmentRelationship not the value of the key field in Attachment 968e22b8-e4fb-4743-bf08-8ac9cd8ecd56 but the value of its id field 10? Is the association defined incorrectly? how to define it?

The 7 of

PS: target_id corresponds to the value of the cid field in the commentDetail record with an id of 4 is correct.

public function create(array $attributes = [], array $joining = [], $touch = true) { $instance = $this->related->newInstance($attributes); // Once we save the related model, we need to attach it to the base model via // through intermediate table so we'll use the existing "attach" method to // accomplish this which will insert the record and any more attributes. $instance->save(['touch' => false]); $this->attach($instance->getKey(), $joining, $touch); return $instance; }