Need help in creating a database schema - django

Question

Current Database Schema -
I have these 3 tables, Curriculum, Assignment, and Student. Every Student is assigned a Curriculum through a ForeginKey relationship between Student and Curriculum. Every
Assignment possesses the same relation with the Curriculum using a ForeginKey.
Problem Statement -
There are around 100 Assignments for each Curriculum, the problem is, some students need to be exempt from some assignments, so I want a way that I can exempt a Student from Assignments 1, 2, and 3 but have the rest of the students do the assignment 1, 2 and 3.
My solution that failed -
What I tried was, creating a ManyToManyField in Student table in relation to Assignment table. However, having to add hundreds of assignments manually would be ridiculously time-consuming for each student.
class Curriculum(models.Model):
name = models.CharField(max_length=50, null=False)
subject = models.CharField(max_length=30, choices=SUBJECT)
grade_level = models.CharField(max_length=20, choices=CURRICULUMGRADE, null=False)
tracking = models.CharField(max_length=20, choices=TRACKING, null=False)
required = models.CharField(max_length=20, null=True)
recorded_from = models.CharField(max_length=20, choices=RECORDED, null=False)
semesterend = models.CharField(max_length=50, null=True)
username = models.CharField(max_length=50, null=True)
password = models.CharField(max_length=50, null=True)
loginurl = models.CharField(max_length=100, null=True)
weight = models.IntegerField(null=True)
level = models.CharField(max_length=20, choices=LEVEL, null=False)
class Student(models.Model):
epicenter_id = models.CharField(
null=False, blank=False, unique=True, max_length=10
)
last_name = models.CharField(null=False, max_length=50)
first_name = models.CharField(null=False, max_length=50)
email = models.EmailField(null=False, max_length=120)
phone_number = models.CharField(null=False, max_length=50)
additional_email = models.EmailField(max_length=120, null=True)
additional_phone_number = models.CharField(max_length=20, null=True)
grade = models.CharField(max_length=20, choices=GRADELEVEL, null=False)
curriculum = models.ForeginKey('curriculum', null=True, blank=True, on_delete=models.SET_NULL)
class Assignment(models.Model):
standard = models.ManyToManyField(
Standard)
curriculum = models.ForeignKey(
Curriculum, on_delete=models.CASCADE, related_name="curriculum_assignment"
)
name = models.CharField(max_length=500, null=False)
description = models.CharField(max_length=500, null=False)
status = models.CharField(max_length=30, choices=STATUS, null=False)
type_of = models.CharField(max_length=30, choices=TYPE, null=False)

Answer 1

Alright, so the best solution I could think of was creating another table to store all the exempted assignments, called ExemptAssignements.
models.py
class ExemptAssignments(models.Model):
student = models.ForeginKey('student', null=True, blank=True, on_delete=models.SET_NULL)
assignments = models.ManyToMany('assignment', null=True, blank=True)
Now anytime I want to exempt the students from any Assignments, I can manually select them through the admin panel, as well the Student who's being exempted.
Now to get a list of all the assignments excluding the ones I have exempted I can simply use.
student = Student.objects.first()
Assignment.objects.filter(curriculum=student.curriculum).exclude(id__in=[x.id for x i in ExemptAssignment.objects.filter(student=student).assignment.all()]
And the above query will only show the Assignments which haven't been exempted.