Django Tutorial Part 2

8. Django Shell 사용하기

polls/models.py

from django.db import models

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')
    
    def __str__(self):
        return f'제목: {self.question_text}, 날짜: {self.pub_date}'

class Choice(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

    def __str__(self):
        return f'{self.choice_text}'

 

Django Shell 실행하기

python manage.py shell

#models.py 파일에 정의된 모든 모델 가져오기
>>> from polls.models import *
>>> Question


#모든 Question,Choice 오브젝트 가져오기
>>> Question.objects.all()
>>> Choice.objects.all()

#첫번째 Choice 오브젝트 가져오기
>>> choice = Choice.objects.all()[0]
>>> choice.id
>>> choice.choice_text
>>> choice.votes

#첫번째 Choice와 연결된 Question 가져오기
>>> choice.question
>>> choice.question.pub_date
>>> choice.question.id


#해당 Question과 연결되어 있는 모든 Choice 가져오기 
>>> question.choice_set.all()

 

 

9. Django Shell - 현재 시간 구하기

# datetime 활용
>>> from datetime import datetime
>>> datetime.now()

# timezone 활용
>>> from django.utils import timezone
>>> timezone.now()

 

 

10. Django Shell - 레코드 생성하기

>>> from polls.models import *

>>> q1 = Question(question_text = "커피 vs 녹차")

>>> from django.utils import timezone
>>> q1.pub_date = timezone.now()

>>> q1.save()

 

polls/models.py

from django.db import models

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField(auto_now_add=True)

>>> q3 = Question(question_text = "abc")
>>> q3.pub_date = timezone.now()
>>> q3.save()

>>> q3.choice_set.create(choice_text = "b")

>>> choice_c = Choice(choice_text='c', question=q3)

>>> choice_c.save()

 

11. Django Shell - 레코드 수정 및 삭제 하기

>>> from polls.models import *

# 수정하기
>>> q = Question.objects.last()
>>> q.question_text = q.question_text + '???'
>>> choice = Question.objects.last()

# 삭제하기
>>> choice.queston.choice_set.all()
>>> choice.delete()

 

 

12. Django Shell - 모델 필터링(Model Filtering)

>>> from polls.models import *

# get() 활용  
>>> Question.objects.get(id=1)
>>> q = Question.objects.get(question_text__startswith='휴가를')
>>> Question.objects.get(pub_date__year=2023) # 에러발생
polls.models.Question.MultipleObjectsReturned: get() returned more than one Question

# filter() 활용
>>> Question.objects.filter(pub_date__year=2023)
<QuerySet [<Question: 제목: 휴가를 어디서 보내고 싶으세요?, 날짜: 2023-02-05 18:52:59+00:00>, <Question: 제목: 가장 좋아하는 디저트는?, 날짜: 2023-02-05 18:53:27+00:00>, ...]>
>>> Question.objects.filter(pub_date__year=2023).count()

#쿼리셋의 SQL 쿼리
>>> Question.objects.filter(pub_date__year=2023).query
>>> print(Question.objects.filter(pub_date__year=2023).query)
SELECT "polls_question"."id", "polls_question"."question_text", "polls_question"."pub_date" FROM "polls_question" WHERE "polls_question"."pub_date" BETWEEN 2023-01-01 00:00:00 AND 2023-12-31 23:59:59.999999

>>> Question.objects.filter(question_text__startswith='휴가를').query
>>> print(Question.objects.filter(question_text__startswith='휴가를').query)
SELECT "polls_question"."id", "polls_question"."question_text", "polls_question"."pub_date" FROM "polls_question" WHERE "polls_question"."question_text" LIKE 휴가를% ESCAPE '\'

>>> q = Question.objects.get(pk=1)
>>> q.choice_set.all()
>>> print(q.choice_set.all().query)
SELECT "polls_choice"."id", "polls_choice"."question_id", "polls_choice"."choice_text", "polls_choice"."votes" FROM "polls_choice" WHERE "polls_choice"."question_id" = 1

 

 

13. 모델 필터링(Model Filtering) 2

>>> from polls.models import *

# startswith 활용
>>> q = Question.objects.filter(question_text__startswith='휴가를')
>>> q2 = Question.objects.filter(pub_date__year=2023)

# contains 활용
>>> Question.objects.filter(question_text__contains='휴가')

>>> Choice.objects.all()
>>> Choice.objects.filter(votes__gt=0)

# 쿼리셋 SQL 쿼리
>>> Choice.objects.filter(votes__gt=0).query
>>> print(Choice.objects.filter(votes__gt=0).query)
SELECT "polls_choice"."id", "polls_choice"."question_id", "polls_choice"."choice_text", "polls_choice"."votes" FROM "polls_choice" WHERE "polls_choice"."votes" > 0

>>> choice=Choice.objects.first()
>>> choice.votes=5
>>> choice.save()

# 정규표현식 활용
>>> Question.objects.filter(question_text__regex=r'^휴가.*어디')
>>> print(Question.objects.filter(question_text__regex=r'^휴가.*어디').query)
SELECT "polls_question"."id", "polls_question"."question_text", "polls_question"."pub_date", "polls_question"."owner_id" FROM "polls_question" WHERE "polls_question"."question_text" REGEXP ^휴가.*어디

 

 

14. Django 모델 관계기반 필터링

polls/models.py

from django.db import models

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')
    
    def __str__(self):
        return f'제목: {self.question_text}, 날짜: {self.pub_date}'
        
class Choice(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)
    def __str__(self):
        return f'[{self.question.question_text}] {self.choice_text}'

>>> from polls.models import *

>>> Choice.objects.filter(question__question_text__startswith='휴가')

# exclude() 활용
>>> Question.objects.exclude(question_text__startswith='휴가')

 

 

15. Django Shell - 모델 메소드

polls/models.py

from django.utils import timezone
import datetime

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')
    
    def was_published_recently(self):
        return self.pub_date >= timezone.now() - datetime.timedelta(days=1)
    
    def __str__(self):
        if self.was_published_recently():
            new_badge = 'NEW!!!'
        else:
            new_badge = ''
        return f'{new_badge} 제목: {self.question_text}, 날짜: {self.pub_date}'