Laravel 如何获取多态多对多关系子查询的自动 id 列名

下面的函数允许我检索给定模型类型的相关条目，这些条目具有例如与其相关联的重叠标签.

<?php

public function getRelated($entity, $fields = [], $relations = []) {
    $related = new EloquentCollection();

    // get models of same entity type that have relations in common

    if (count($relations)) {
        foreach ($relations as $relation) {
            // check if the current model in use has any of the currently iterated relationship at all
            if ($entity->{$relation}()->exists()) {
                // if yes, get all the ids of the related models, for instance tags
                $relationIds = $entity->{$relation}()->get()->pluck('id')->toArray();

                // now, get all same type models except the current one
                $relationEntities = $this->entity::whereNot('id', $entity->id)
                    // also except the ones we already found
                    ->whereNotIn('id', $related->modelKeys())
                    // and only get those which also have current relationship (e.g. tags)
                    ->whereHas($relation, function (Builder $query) use($relationIds, $relation) {
                        $query->whereIn($relation . '.id', $relationIds);
                    })
                    ->get()
                    ->sortKeysDesc()
                    ->take(10);

                $related = $related->concat($relationEntities->except($related->modelKeys()));
            }
        }
    }
}

这样做效果很好.例如，我可以加载一篇博客文章，并通过调用以下命令来显示具有一些相同标签的相关博客文章:

$post = Post::find(1);
$related = $this->getRelated($post, [], ['tags']);

现在，我还需要尊重除标记之外的其他类型，因此$relations是一个数组:"向我展示具有任何这些标记、类别等共同之处的相关博客文章."

我的第一个问题是在子查询中.I had to hardcode the id in the relation table:

$query->whereIn('id', $relationIds);
had to be
$query->whereIn($relation . '.id', $relationIds);

所以现在我的问题是，$relation . '.id'并不是适用于所有情况.关系fooBars()期望foo_bar.id，但看起来是fooBar.id.

没有自动的方法让Laravel根据我当前查询的关系自动知道列名吗？如果不是，我必须为我要查询的每个关系定义关系表的列名(Id).我是不是漏掉了什么？

或者我可以以某种方式加载关系并查看数据库方案？这里的最佳实践是什么？

一种方法是使用蛇形shell ($query->whereIn(Str::of($relation)->snake() . '.id', $relationIds);)，但这感觉既模糊又肮脏.

所有这些都是多态的MoryToMany/MorphedByMany.

编辑:为了更好地理解，我添加了一个我的模型看起来像什么的例子.它们都使用默认命名约定.同样，我想获得相关的帖子，要么有一些共同的标签，要么有共同的FooBars.

<?php

class Post extends Entity
{
    public function tags()
    {
        return $this->morphToMany(Tag::class, 'taggable');
    }

    public function fooBars()
    {
        return $this->morphToMany(FooBar::class, 'foo_barable');
    }    
}

class Tag extends Entity
{
    public function posts()
    {
        return $this->morphedByMany(Post::class, 'taggable');
    }
}

class FooBar extends Entity
{
    public function posts()
    {
        return $this->morphedByMany(Post::class, 'foo_barable');
    }
}

感谢@KGG的回答，我想出了以下几点:

<?php

if (count($relations)) {
    foreach ($relations as $relation) {
        if ($entity->{$relation}()->exists()) {
            $relationIds = $entity->{$relation}()->get()->modelKeys();
            $relatedClass = get_class($entity->$relation()->getRelated());
            $relationPrimaryKey = ($instance = new $relatedClass)->getQualifiedKeyName();

            $relationEntities = $this->entity::whereNot('id', $entity->id)
                ->whereNotIn('id', $related->modelKeys())
                ->whereHas($relation, function (Builder $query) use($relationIds, $relationPrimaryKey) {
                    $query->whereIn($relationPrimaryKey, $relationIds);
                })
                ->get()
                ->sortKeysDesc()
                ->take(10)
                ;

            $related = $related->concat($relationEntities->except($related->modelKeys()));
        }
    }
}