python - Django: ForeignKey Filter 查询Form中选中的数据

Question

我正在使用自动结果系统应用程序。我在 models.py 文件中有五个模型类。

class Student(models.Model):
    std_name=models.CharField('Student Name ', max_length=200)
    CLASS_NAME=(
        ('6','SIX'),
        ('7','SEVEN'),
        ('8','Eight'),
        ('9','Nine'),
        ('10','Ten'),
        ('Ex-10','EX-Ten'),
    )
    std_class_name=models.CharField('Class Name', max_length=7, choices=CLASS_NAME)
    std_roll_number=models.IntegerField('Roll Number')
    GENDER=(
        ('Male','Male'),
        ('Female','Female'),
    )
    std_gender=models.CharField('Gender', max_length=7, choices=GENDER)
    GROUP=(
        ('Science','Science Group'),
        ('B.Studies','Business Group'),
        ('Arts and Humatics','Arts and Humatics'),
        ('General','General'),
    )
    std_group=models.CharField('Group', max_length=17, choices=GROUP)
    pub_date = models.DateTimeField('Published', auto_now_add=True)
    std_total_subject=models.IntegerField('Total Subject', default=0)


    def __str__(self):
        return self.std_name



class ExaminationName(models.Model):
    examination_name=models.CharField('Examination Name ', max_length=100)
    exam_date=models.DateTimeField('Exam Date: ')
    pub_date = models.DateTimeField('Published', auto_now_add=True)


    def __str__(self):
        return self.examination_name

class MainSubject(models.Model):
    main_subject_name = models.CharField('Main Subject Name', max_length=100)
    main_subject_code=models.DecimalField('Main Subject Code', decimal_places=0, default=0, max_digits=10)
    subject_full_marks = models.DecimalField('Subject Full Marks', max_digits=6, decimal_places=0, default=100)
    pub_date = models.DateTimeField('Published', auto_now_add=True)

    def __str__(self):
        return self.main_subject_name



class SubjectName(models.Model):
    mainsubject = models.ForeignKey(MainSubject, on_delete=models.CASCADE)
    subject_name=models.CharField('Subject Name', max_length=100)
    subject_full_marks=models.DecimalField('Subject Full Marks',max_digits=6, decimal_places=0, default=100)
    pub_date = models.DateTimeField('Published', auto_now_add=True)

    subject_gpa_point=models.DecimalField('GPA in Subject',max_digits=4, decimal_places=2, default=0)
    subject_gpa_grade=models.CharField('GPA Grade',max_length=5, default='F')


    def __str__(self):
        return self.subject_name


class SubjectPart(models.Model):
    mainsubject = models.ForeignKey(MainSubject, on_delete=models.CASCADE)
    subjectname = models.ForeignKey(SubjectName, on_delete=models.CASCADE)
    subject_part_name=models.CharField('Subject Part', max_length=100)
    subject_part_full_marks = models.DecimalField('Full Marks', max_digits=6, decimal_places=0, default=100)
    subject_part_pass_marks = models.DecimalField('Pass Marks', max_digits=6, decimal_places=0, default=100)
    pub_date = models.DateTimeField('Published', auto_now_add=True)


    def __str__(self):
        return self.subject_part_name






class AddResult(models.Model):
    student=models.ForeignKey(Student, on_delete=models.CASCADE)
    examinationname = models.ForeignKey(ExaminationName, on_delete=models.CASCADE)
    mainsubject_name = models.ForeignKey(MainSubject, on_delete=models.CASCADE)
    subjectname = models.ForeignKey(SubjectName, on_delete=models.CASCADE)
    subjectpart = models.ForeignKey(SubjectPart, on_delete=models.CASCADE)
    subject_number=models.DecimalField('Subject Number', max_digits=6, decimal_places=0)
    pub_date = models.DateTimeField('Published', auto_now_add=True)


    def __str__(self):
        return str(self.subjectpart)

    def fail_sub(self):
        if self.subject_number < self.subjectpart.subject_part_pass_marks:
            return 'F'

我已经通过 Django 管理面板创建了一个 MainSubject 对象。我通过外键在 SubjectName 模型类中添加了主要主题。 我在 SubjectName 模型类中创建了两个外键。我通过这样的 Django 管理面板在 SubjectPart 模型中创建了任何对象。

然后我创建了一个 AddResulForm ModelForm。但问题是当我选择主题名称时，所有主题都会显示那个时间。如果我选择 Bangla 作为 Main subject，那么我在 Subject Name Part 中只选择 Bangla First Part 或 Bangla 2nd Part。但是现在以这种形式显示所有主题。 如何在 Django 表单中实现我的想法？

Answer 1

为此，您应该在 admin.py 中编写方法

您可以为模型(主题部分)创建一个类并为该字段实现一个方法。

可以引用这个https://docs.djangoproject.com/en/1.11/ref/contrib/admin/