Add task model

At the end of this guide you will:

• create a Django model to represent tasks
• create and apply migrations to the project database

Make sure you have successful configured PostgreSQL database before you begin.

Table of Contents Getting started Task model UML diagram Guide Create task model Changes

Getting started

git checkout bp-models-tasks

Task model UML diagram

erDiagram
    task {
        UUID uuid "primary key"
        string summary
        string description
        bool completed
        datetime created_at
        datetime updated_at
        bigint reporter "foreign key"
        bigint assignee "foreign key"
    }

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Guide

Create task model

# tasks/models.py
"""
Tasks application models

"""

import uuid

from django.contrib.auth import get_user_model
from django.db import models

UserModel = get_user_model()


class TaskModel(models.Model):
    """
    Task model implementation

    :ivar uuid: primary key
    :type uuid: :class: `uuid.UUID`
    :ivar summary: title, or short description (up to 128 characters).
    :type summary: str
    :ivar description: detailed description, defaults to None.
    :type description: str
    :ivar completed: completed status, defaults to False.
    :type completed: bool
    :ivar created_at: created timestamp, non-editable.
    :type created_at: :class: `datetime.datetime`
    :ivar updated_at: updated timestamp, non-editable.
    :type updated_at: :class: `datetime.datetime`
    :ivar assignee: reference to a user that task is assigned to.
    :type assignee: :class: `UserModel`, optional
    :ivar reporter: reference to a user that created the task.
    :type reporter: :class: `UserModel`

    Represents a tasks registered in the system.
    Each new task is created as uncompleted by default.
    Each task gets its ``created_at`` timestamp once on task creation.
    Each task updates its ``updated_at`` timestamp on each task save.

    """

    uuid = models.UUIDField(
        default=uuid.uuid4,
        editable=False,
        primary_key=True,
        verbose_name="primary key",
    )

    summary = models.CharField(
        max_length=128,
        help_text="Required. 128 characters or fewer."
    )
    description = models.TextField(
        blank=True,
        default="",
    )
    completed = models.BooleanField(
        default=False,
        verbose_name="completed status"
    )

    # task metadata
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    # relationships
    assignee = models.ForeignKey(
        UserModel,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="tasks_assigned",
        verbose_name="assigned to",
    )
    reporter = models.ForeignKey(
        UserModel,
        on_delete=models.PROTECT,
        related_name="tasks_reported",
        verbose_name="reported by",
    )

    @property
    def title(self) -> str:
        return str(self)

    def __str__(self) -> str:
        """Return a string version of an instance"""

        return self.summary

Changes

1. Full change log