Laravel Eloquent with()方法在PostgreSQL下报错求助

在Laravel 10.7.1 + PHP 8.1.17 + PostgreSQL环境下，调用Eloquent的with()方法预加载关联模型时触发如下错误：

SQLSTATE[42883]: Undefined function: 7 ERROR: operator does not exist: uuid = integer LINE 1:

但使用$modelParent->parentChilds()->createMany([...data])创建关联数据时无报错。

表结构 #

parents
--------
id (uuid)
name (string)
user_id (uuid)
description (text)

details
---------
id (uuid)
parent_id (uuid)
title (string)
description (tinytext)

控制器代码 #

/**
 * Display the specified resource.
 */
public function show(string $id)
{
    $this->authorize('viewParent', \App\Models\Parent::class);

    $model = \App\Models\Parent::with(['user', 'parentChilds'])->findOrFail($id);

    return view("$this->view.show", [
        'model' => $model,
        'title' => "$this->title",
        'route' => $this->route,
    ]);
}

Parent模型代码 #

/**
 * The attributes that are mass assignable.
 *
 * @var array
 */
protected $fillable = [
    'title',
    'user_id',
    'description',
];

/**
 * The attributes that should be cast to native types.
 *
 * @var array
 */
protected $casts = [
    'id' => 'string',
];

/**
 * Get the user that owns the MinuteOfMeeting
 *
 * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
 */
public function user(): BelongsTo
{
    return $this->belongsTo(User::class, 'user_id')->withTrashed();
}

/**
 * Get all of the minuteOfMeetingDetails for the MinuteOfMeeting
 *
 * @return \Illuminate\Database\Eloquent\Relations\HasMany
 */
public function parentChilds(): HasMany
{
    return $this->hasMany(ParentChild::class, 'parent_id', 'id');
}

错误的Child模型代码 #

/**
 * The attributes that are mass assignable.
 *
 * @var array
 */
protected $fillable = [
    'parent_id',
    'title',
    'description'
];

/**
 * The attributes that should be cast to native types.
 *
 * @var array
 */
protected $casts = [
    'id' => 'string',
    'parent_id' => 'string',
];

/**
 * Get the minuteOfMeeting that owns the MinuteOfMeetingDetail
 *
 * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
 */
public function parent(): BelongsTo
{
    return $this->belongsTo(Parent::class, 'parent', 'id')->withTrashed();
}

错误原因 #

Child模型的parent()关联方法中，belongsTo的外键参数错误，传入了'parent'，但实际表中存储关联的字段是parent_id。当Laravel执行预加载查询时，会尝试用不存在的parent字段（默认被识别为integer类型）去关联parents表的uuid类型id字段，导致PostgreSQL抛出类型不匹配的运算符错误。

而createMany()方法正常是因为该方法从Parent模型的parentChilds()关联出发，使用正确的parent_id外键写入数据，不会触发反向关联的查询逻辑。

修复方案 #

修改Child模型的parent()关联方法，将外键参数改为'parent_id'：

/**
 * Get the minuteOfMeeting that owns the MinuteOfMeetingDetail
 *
 * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
 */
public function parent(): BelongsTo
{
    return $this->belongsTo(Parent::class, 'parent_id', 'id')->withTrashed();
}

内容的提问来源于stack exchange，提问作者Zulfikar Ditya