laravel 中的学生和老师以及课程关系

Question

我的 Laravel 项目中的关系有问题：

---

我的项目包括：

• 学生（ID-姓名-手机-电子邮件）
• 教师（ID - 姓名 - 手机 - 电子邮件）
• 课程（ID - 名称 - 描述）

---

关系：

• 每门课程由一位或多位教师提供。
• 每位教师提供一门或多门课程。
• 每位学生注册一门或多门课程。
• 每位学生都参加了一位老师的一门或多门课程

---

澄清：

• 课程和老师 =（多对多）。
• 课程和学生 =（多对多）。
• 学生和老师 =（多对多）。

---

通过我的搜索发现： 接下来的两张图片..这些关系是真的吗？

---

---

我的工作：

- 迁移：

Schema::create('courses', function (Blueprint $table) {
            $table->increments('id')->unsigned();
            $table->string('name');
            $table->text('description');

            $table->timestamps();
        });


Schema::create('students', function (Blueprint $table) {
            $table->increments('id')->unsigned();
            $table->string('name');
            $table->string('mobile');
            $table->string('email');

            $table->timestamps();
        });


Schema::create('teachers', function (Blueprint $table) {
            $table->increments('id')->unsigned();
            $table->string('name');
            $table->string('mobile');
            $table->string('email');

            $table->timestamps();
        });


Schema::create('enrollments', function (Blueprint $table) {
            $table->increments('id')->unsigned();
            $table->integer('course_id')->unsigned();
            $table->integer('student_id')->unsigned();

            $table->foreign('course_id')->references('id')->on('courses')->onDelete('cascade');
            $table->foreign('student_id')->references('id')->on('students')->onDelete('cascade');

            $table->timestamps();
        });


Schema::create('teaches', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('course_id')->unsigned();
            $table->integer('teacher_id')->unsigned();

            $table->foreign('course_id')->references('id')->on('courses')->onDelete('cascade');
            $table->foreign('teacher_id')->references('id')->on('teachers')->onDelete('cascade');

            $table->timestamps();
        });


Schema::create('student_course_teacher', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('enroll_student_id')->unsigned();
            $table->integer('enroll_course_id')->unsigned();
            $table->integer('teach_teacher_id')->unsigned();

            $table->foreign('enroll_student_id')->references('student_id')->on('enrollments')->onDelete('cascade');
            $table->foreign('enroll_course_id')->references('course_id')->on('enrollments')->onDelete('cascade');
            $table->foreign('teach_teacher_id')->references('teacher_id')->on('teaches')->onDelete('cascade');

            $table->timestamps();
        });

---

- 型号：

- 课程：

class Course extends Model
{
    protected $table = 'courses';

    public function students()
    {
        return $this->belongsToMany(Student::class, 'enrollments', 'student_id', 'course_id')->withTimestamps();
    }

    public function teachers()
    {
        return $this->belongsToMany(Teacher::class, 'teaches', 'teacher_id', 'course_id')->withTimestamps();
    }
}

- 学生：

class Student extends Model
{
    protected $table = 'students';

    public function courses()
    {
        return $this->belongsToMany(Course::class, 'enrollments', 'course_id', 'student_id')->withTimestamps();
    }
}

- 老师：

class Teacher extends Model
{
    protected $table = 'teachers';

    public function courses()
    {
        return $this->belongsToMany(Course::class, 'teaches', 'course_id', 'teacher_id')->withTimestamps();
    }
}

- 注册：

class Enrollment extends Model
{
    protected $table = 'enrollments';

}

- 教：

class Teach extends Model
{
    protected $table = 'teaches';

}

注意：我无法在（Enrollment & Teach）中建立关系。

我的要求：

• 完整的关系
• 我想为某门课程的学生提供教师信息。
• 我想和她的学生和老师一起上课。
• 我想与学生一起参加某些教师课程。

等待帮助，

Answer 1

这显然没有经过测试，但应该可以帮助您找到解决问题的方法。

表格名称

1. 课程（用于课程模型）
2. 学生（学生模型）
3. 教师（教师模式）
4. course_student（针对学生与课程之间的多对多关系）- 为此，您将创建一个额外的模型 (CourseStudent)，该模型实际上将用于第 6 点。
5. course_teacher（用于教师与课程之间的多对多关系）
6. course_student_teacher（针对 CourseStudent 和教师之间的多对多关系）

模型

课程模式

class Course extends Model
{
  public function students()
  {
    return $this->belongsToMany(Student::class)->withTimestamps();
  }

  public function teachers()
  {
    return $this->belongsToMany(Teacher::class)->withTimestamps();
  }
}

学生模型

class Student extends Model
{
  public function courses()
  {
    return $this->belongsToMany(Course::class)->withTimestamps();
  }
}

教师模式

class Teacher extends Model
{
  public function courses()
  {
    return $this->belongsToMany(Course::class)->withTimestamps();
  }

  // Courses/Students Currently Being Taught
  public function courseStudents()
  {
    return $this->belongsToMany(CourseStudent::class, 'course_student_teacher')
                ->withTimestamps();
  }

  // List Of Students Currently Taught For Different Courses
  public function allStudentsCurrentlyTaught()
  {
    return $this->courseStudents()->get()->map(function($courseStudent) {
      return $courseStudent->student;
    })->unique('id');
  }

  // List Of Courses Currently Taught To Different Students
  public function coursesCurrentlyTaughtToStudents()
  {
    return $this->courseStudents()->get()->map(function($courseStudent) {
      return $courseStudent->course;
    })->unique('id');
  }

  // List Of Courses Taught To A Particular Students
  public function coursesTaughtToAStudent($studentId)
  {
    return $this->courseStudents()->get()->where('student_id', $studentId)->map(function($courseStudent) {
      return $courseStudent->course;
    });
  }

  // List Of Students Taught For A Particular Course
  public function coursesTaughtForACourse($courseId)
  {
    return $this->courseStudents()->get()->where('course_id', $courseId)->map(function($courseStudent) {
      return $courseStudent->course;
    });
  }
}

CourseStudent 模型用于创建数据透视表course_student_teacher

class CourseStudent extends Model
{
  protected $table = 'course_student';

  public function course()
  {
    return $this->belongsTo(Course::class)->withTimestamps();
  }

  public function student()
  {
    return $this->belongsTo(Student::class)->withTimestamps();
  }

  public function teachers()
  {
    return $this->belongsToMany(Teacher::class, 'course_student_teacher')->withTimestamps();
  }
}