Question

I want to create a minimalist task management app to learn Django’s basics. So there will be Projects , Tasks and Users as the three big entities.

• A Project can have multiple users
• A Project can have multiple tasks
• A task can be assigned to 1 user

I can unable to figure out how to do a Many-to-One from Project – > Users using django.contrib.auth.models.User as my Users source.

This is what I have so far, but I know it is wrong and I am unable to wrap my head around it. I tried to relate to other questions such as the one with Contestents and the one with Vulnerabilities URLS on StackOverflow. I am not sure if I have to write my own User Model, or somehow extend it.

class Project(models.Model):
    Project_Name = models.CharField(max_length=100)
    Project_Users = models.ManyToManyField(User)

class Tasks(models.Model):
    Task_Name = models.CharField(max_length=300)
    Task_AssignedToUser = models.ForeignKey("Project_Name", through=Users)

Thank you for your help.

Answer 1

class Project(models.Model):
    name = models.CharField(max_length=100)
    users = models.ManyToManyField(User)

class Task(models.Model):
    project = models.ForeignKey(Project, related_name='project_tasks')
    name = models.CharField(max_length=300)
    assignee = models.ForeignKey(User, related_name='tasks')

Get the the users participating in a specific project:

p = Project.objects.get(name='myproject')
users = p.users.all()

Get a project’s tasks:

users = p.project_tasks.all()  # Because of `related_name` in Task.project

Get All the tasks a user has, of all the projects:

u = User.objects.get(username='someuser')
u.tasks.all()  # Because of `related_name` in Task.assignee

Notes:

1. A ForeignKey is a Many to One relationship. e.g. A Task belongs to only one Project – A Project can have many Tasks.

2. You don’t need superfluous field names. name is better than Project_Name

3. One question at a time.