models.py

https://docs.djangoproject.com/ko/3.2/topics/db/models/
https://brunch.co.kr/magazine/django-doc

간단한 구조

• models.py

from django.db import models

class Person(models.Model):
    first_name = models.CharField(max_length=30)
    last_name = models.CharField(max_length=30)

• sql문

CREATE TABLE myapp_person (
    "id" serial NOT NULL PRIMARY KEY,
    "first_name" varchar(30) NOT NULL,
    "last_name" varchar(30) NOT NULL
);

• 일반적인 모델

from django.db import models

class MyModelName(models.Model):
    """A typical class defining a model, derived from the Model class."""

    # Fields
    my_field_name = models.CharField(max_length=20, help_text='Enter field documentation')
    ...

    # Metadata
    class Meta:
        ordering = ['-my_field_name']

    # Methods
    def get_absolute_url(self):
        """Returns the url to access a particular instance of MyModelName."""
        return reverse('model-detail-view', args=[str(self.id)])

    def __str__(self):
        """String for representing the MyModelName object (in Admin site etc.)."""
        return self.field_name

필드

https://brunch.co.kr/@ddangdol/1

모델에서 가장 중요하고, 유일하게 필수적인 부분은 데이터베이스 필드 목록을 정의하는 것입니다. 필드는 클래스 속성으로 정의됩니다. clean, save, delete 같은 :doc:모델 API와 충돌할 수 있는 단어를 필드 이름으로 사용하지 않도록 주의하세요.

from django.db import models

class Musician(models.Model):
    first_name = models.CharField(max_length=50)
    last_name = models.CharField(max_length=50)
    instrument = models.CharField(max_length=100)

class Album(models.Model):
    artist = models.ForeignKey(Musician, on_delete=models.CASCADE)
    name = models.CharField(max_length=100)
    release_date = models.DateField()
    num_stars = models.IntegerField()

Field Option

https://brunch.co.kr/@ddangdol/3

• null
• blank
• choice
• db_column
• db_index
• db_tablespace
• default
• editable
• error_messages
• help_text
• primary_key
• unique
• verbose_name
• validators

Field Type

https://docs.djangoproject.com/ko/3.2/ref/models/fields/#field-types
https://brunch.co.kr/@ddangdol/4

• AutoField(**options)
• BigAutoField(**options)
• BigIntegerField(**options)
• BinaryField(max_length=None, **options)
• BooleanField(**options)
• CharField(max_length=None, **options)
  • For large amounts of text, use TextField.
• DateField(auto_now=False, auto_now_add=False, **options)
• DateTimeField(auto_now=False, auto_now_add=False, **options)
• DecimalField(max_digits=None, decimal_places=None, **options)
• DurationField(**options)
• EmailField(max_length=254, **options)
• FileField(upload_to=None, max_length=100, **options)
• FilePathField(path='', match=None, recursive=False, allow_files=True, allow_folders=False, max_length=100, **options)
• FloatField(**options)
• ImageField(upload_to=None, height_field=None, width_field=None, max_length=100, **options)
• IntegerField(**options)
• GenericIPAddressField(protocol='both', unpack_ipv4=False, **options)
• JSONField(encoder=None, decoder=None, **options)
• NullBooleanField(**options)
• PositiveBigIntegerField(**options)
• PositiveIntegerField(**options)
• PositiveSmallIntegerField(**options)
• SlugField(max_length=50, **options)
• SmallAutoField(**options)
• SmallIntegerField(**options)
• TextField(**options)
• TimeField(auto_now=False, auto_now_add=False, **options)
• URLField(max_length=200, **options)
• UUIDField(**options)

Relationship fields

https://docs.djangoproject.com/ko/3.2/ref/models/fields/#module-django.db.models.fields.related
https://brunch.co.kr/@ddangdol/5

• ForeignKey(to, on_delete, **options)
• ManyToManyField(to, **options)
  • https://brunch.co.kr/@ddangdol/6
• OneToOneField(to, on_delete, parent_link=False, **options)
  • https://brunch.co.kr/@ddangdol/10

meta 데이터

https://docs.djangoproject.com/en/2.0/ref/models/options/#model-meta-options

아래와 같이 class Meta를 선언하여 모델에 대한 모델-레벨의 메타데이타를 선언

class Meta:
    ordering = ['-my_field_name']

모델 타입을 쿼리(query)할 때 반환되는 기본 레코드 순서를 제어
예를 들어, 우리가 기본적으로 아래와 같이 책들을 정렬하려고 한다면:

ordering = ['title', '-pubdate']

책들은 A-Z까지 알파벳 순으로 정렬되고, 그 후에는 제목(title) 안에 있는 발행일 별로 가장 최근 것부터 가장 오래된 것 순으로 정렬

model methods

비지니스 로직을 담는 곳

from django.db import models

class Person(models.Model):
    name = models.CharField(max_length=128)

    def __str__(self):
        return self.name

class Person(models.Model):
    first_name = models.CharField(max_length=50)
    last_name = models.CharField(max_length=50)
    birth_date = models.DateField()

    def baby_boomer_status(self):
        "Returns the person's baby-boomer status."
        import datetime
        if self.birth_date < datetime.date(1945, 8, 1):
            return "Pre-boomer"
        elif self.birth_date < datetime.date(1965, 1, 1):
            return "Baby boomer"
        else:
            return "Post-boomer"

    @property
    def full_name(self):
        "Returns the person's full name."
        return '%s %s' % (self.first_name, self.last_name)

Model inheritance

https://docs.djangoproject.com/en/3.2/topics/db/models/#model-inheritance

from django.db import models

class CommonInfo(models.Model):
    name = models.CharField(max_length=100)
    age = models.PositiveIntegerField()

    class Meta:
        abstract = True
        ordering = ['name']

class Unmanaged(models.Model):
    class Meta:
        abstract = True
        managed = False

class Student(CommonInfo, Unmanaged):
    home_group = models.CharField(max_length=5)

    class Meta(CommonInfo.Meta, Unmanaged.Meta):
        pass