Django 점적(5)---모델링

ORM은 데이터베이스 모델링에 편리함을 가져왔다.
https://docs.djangoproject.com/en/dev/topics/db/models/
https://docs.djangoproject.com/en/dev/ref/models/fields/#model-field-types
예를 들어 다음 정의는 자동으로 SQL 문을 생성합니다.
 

from django.db import models



class Person(models.Model):

    first_name = models.CharField(max_length=30)

    last_name = models.CharField(max_length=30)

CREATE TABLE myapp_person (

    "id" serial NOT NULL PRIMARY KEY,

    "first_name" varchar(30) NOT NULL,

    "last_name" varchar(30) NOT NULL

);

 
 
공통 필드 필드
AutoField
(
**options
)
BigIntegerField([**options])
BooleanField(**options)
CharField(max_length=None[, **options])
CommaSeparatedIntegerField(max_length=None[, **options])
DateField
(
[
auto_now=False
, 
auto_now_add=False
, 
**options
]
)
DateTimeField([auto_now=False, auto_now_add=False, **op
tions
]
)
DecimalField(max_digits=None, decimal_places=None[, **options])
EmailField([max_length=75, **options])
FileField(upload_to=None[, max_length=100, **options])
FloatField([**options])
ImageField(upload_to=None[, height_field=None, width_field=None, max_length=100, **options])
IntegerField([**options])
IPAddressField([**options])
TextField([**options])
TimeField([auto_now=False, auto_now_add=False, **options])
URLField([max_length=200, **options])
필드 필드의 매개 변수 (options)
null이 null일 수 있는지 여부
blank를 비울 수 있는지 여부
default 기본값
choices 열거 유형

class Student(models.Model):

    FRESHMAN = 'FR'

    SOPHOMORE = 'SO'

    JUNIOR = 'JR'

    SENIOR = 'SR'

    YEAR_IN_SCHOOL_CHOICES = (

        (FRESHMAN, 'Freshman'),

        (SOPHOMORE, 'Sophomore'),

        (JUNIOR, 'Junior'),

        (SENIOR, 'Senior'),

    )

    year_in_school = models.CharField(max_length=2,

                                      choices=YEAR_IN_SCHOOL_CHOICES,

                                      default=FRESHMAN)



    def is_upperclass(self):

        return self.year_in_school in (self.JUNIOR, self.SENIOR)

primary_키가 메인 키인지 여부입니다.키를 지정하지 않으면 자동으로 id 필드를 키로 생성합니다.
유일하다
unique_for_날짜가 유일한지 여부
validator 지정 검증기
verbose_더 좋은 디스플레이 이름 (참고,django/admin은 덮어쓴 모델.Model. unicode () 방법을 사용합니다)
관계 필드 필드 필드
외부 키:

class Car(models.Model):

    manufacturer = models.ForeignKey('Manufacturer')

    # ...



class Manufacturer(models.Model):

    # ...

멀티 페어:

class Topping(models.Model):

    # ...



class Pizza(models.Model):

    # ...

    toppings = models.ManyToManyField(Topping)

다대다간접 관계(Person과 Group은 직접적으로 연결된 것이 아니라through='Membership'을 통해):

class Person(models.Model):

    name = models.CharField(max_length=128)



    def __unicode__(self):

        return self.name



class Group(models.Model):

    name = models.CharField(max_length=128)

    members = models.ManyToManyField(Person, through='Membership')



    def __unicode__(self):

        return self.name



class Membership(models.Model):

    person = models.ForeignKey(Person)

    group = models.ForeignKey(Group)

    date_joined = models.DateField()

    invite_reason = models.CharField(max_length=64)

>>> ringo = Person.objects.create(name="Ringo Starr")

>>> paul = Person.objects.create(name="Paul McCartney")

>>> beatles = Group.objects.create(name="The Beatles")

>>> m1 = Membership(person=ringo, group=beatles,

...     date_joined=date(1962, 8, 16),

...     invite_reason= "Needed a new drummer.")

>>> m1.save()

>>> beatles.members.all()

[<Person: Ringo Starr>]

>>> ringo.group_set.all()

[<Group: The Beatles>]

>>> m2 = Membership.objects.create(person=paul, group=beatles,

...     date_joined=date(1960, 8, 1),

...     invite_reason= "Wanted to form a band.")

>>> beatles.members.all()

[<Person: Ringo Starr>, <Person: Paul McCartney>]

# THIS WILL NOT WORK

>>> beatles.members.add(john)

# NEITHER WILL THIS

>>> beatles.members.create(name="George Harrison")

# AND NEITHER WILL THIS

>>> beatles.members = [john, paul, ringo, george]