雄辩的关系和多维集合拒绝

Question

我有一个学校数据库，其中有很多老师，有很多学生，像这样：

class School extends Model
{
    public function teachers()
    {
        return $this->hasMany(Teacher::class,'school_id');
    }
}

class Teacher extends Model
{
    public function students()
    {
        return $this->hasMany(Student::class,'teacher_id');
    }
}

class Student extends Model
{
}

---

完整查询

$full = School::with(['teachers' => function ($query) {
    $query->with('students');
}])->get();

结果是这样的：

[
    {
        "id": 1,
        "school_name": "First Park",
        "teachers": [
            {
                "id": 1,
                "teacher_name": "Mr.Aha",
                "students": [
                    {
                        "id": 1,
                        "student_name": "Jane",
                        "drop": 1
                    },
                    {
                        "id": 2,
                        "student_name": "Jon",
                        "drop": 0
                    }
                ]
            }
        ]
    }
]

---

现在，我想删除辍学的学生，并选择Teacher_name，因此我尝试用雄辩和收集来做到这一点，但他们都失败了。

雄辩的方法是：

School::with(['teachers' => function ($teacher) {
    $teacher->with(['students' => function ($student) {
        $student->where('drop', '!=', 0)
    }])->select('teacher_name');
}])->get();

但是结果输出，老师是一个空对象。

---

收集方式基于完整查询

$full->map(function ($teacher) {
    unset($teacher->id);//there are more column to unset in real life
    $teacher->reject(function ($student) {
        return $student->drop == 0;
    });
});

但是结果与完整查询相同。

---

我不知道哪种方法更好，更有说服力或有收藏价值，但它们不会起作用

Answer 1

您还必须选择渴望加​​载所需的id和school_id列：

School::with(['teachers' => function ($teacher) {
    $teacher->with(['students' => function ($student) {
        $student->where('drop', '!=', 0)
    }])->select('id', 'school_id', 'teacher_name');
}])->get();

然后将其删除，或使用$ hidden ：

$full->map(function ($teacher) {
    unset($teacher->id, $teacher->school_id);
});

Answer 2

来自原始文档的示例。

嵌套的预先加载要渴望加载嵌套的关系，可以使用“点”语法。 例如，让我们急切地在一项雄辩的陈述中加载本书的所有作者和所有作者的个人联系人：

$ books = App \\ Book :: with（'author.contacts'）-> get（）;

另外，您可以使用load（）方法