數據庫設置
安裝數據庫
mysite/settings.py
SQLite
DATABASES = {
'default': {
'ENGINE':'django.db.backends.sqlite3',
'NAME': 'mydatabase',
}
}MySQL/Oracle/PostgreSQL
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'mydatabase',
'USER': 'mydatabaseuser',
'PASSWORD': 'mypassword',
'HOST': '127.0.0.1',
'PORT': '5432',
}
}安裝應用
mysite/settings.py
默認情況下，INSTALLED_APPS包含以下應用程序，所有這些應用程序都與Django一起提供：
- django.contrib.admin - 管理網站。你會很快使用它。
- django.contrib.auth - 認證系統。
- django.contrib.contenttypes - 內容類型的框架。
- django.contrib.sessions - 會話框架
- django.contrib.messages - 消息框架。
- django.contrib.staticfiles - 管理靜態文件的框架。
創建數據庫
# directory: mysite/manage.py
$ python manage.py migrate創建models
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')
class Choice(models.Model):
question = models.ForeignKey(Question, on_delete=models.CASCADE)
choice_text = models.CharField(max_length=200)
votes = models.IntegerField(default=0)安裝應用
mysite/settings.py
INSTALLED_APPS = [
'polls.apps.PollsConfig',
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
]將polls/models.py 中的類轉換成統一格式，爲生成數據庫中的表做準備
polls/models.py -格式化-> polls/migration/number_comment.py
$ python manage.py makemigrations polls會在polls/migrations/生成如下類似文件
2017/06/17 20:17 1,268 0001_initial.py
2017/06/17 20:17 454 0002_choice_test.py
2017/06/17 20:17 401 0003_remove_choice_test.py
2017/06/17 20:17 447 0004_auto_20170617_1756.py
2017/06/17 20:17 447 0005_auto_20170617_1757.py查看格式化後的文件將運行什麼SQL
$ python manage.py sqlmigrate polls 0001生成的文件，(migrate)運行以在數據庫中創建這些模型表：
$ python manage.py migrate要執行的操作：
應用所有遷移：admin，auth，contenttypes，polls，sessions
運行遷移：
渲染模型狀態… DONE
應用polls.0001_initial … OK
- 編輯或修改polls/models.py文件
- 將models.py格式化
- 執行migrate
進入命令行調試
$ python manage.py shell>>> from polls.models import Question, Choice # Import the model classes we just wrote.
# No questions are in the system yet.
>>> Question.objects.all()
<QuerySet []>
# Create a new Question.
# Support for time zones is enabled in the default settings file, so
# Django expects a datetime with tzinfo for pub_date. Use timezone.now()
# instead of datetime.datetime.now() and it will do the right thing.
>>> from django.utils import timezone
>>> q = Question(question_text="What's new?", pub_date=timezone.now())
# Save the object into the database. You have to call save() explicitly.
>>> q.save()
# Now it has an ID. Note that this might say "1L" instead of "1", depending
# on which database you're using. That's no biggie; it just means your
# database backend prefers to return integers as Python long integer
# objects.
>>> q.id
1
# Access model field values via Python attributes.
>>> q.question_text
"What's new?"
>>> q.pub_date
datetime.datetime(2012, 2, 26, 13, 0, 0, 775217, tzinfo=<UTC>)
# Change values by changing the attributes, then calling save().
>>> q.question_text = "What's up?"
>>> q.save()
# objects.all() displays all the questions in the database.
>>> Question.objects.all()
<QuerySet [<Question: Question object>]>編輯polls/models.py，add __str__() methods to your models
from django.db import models
class Question(models.Model):
# ...
def __str__(self):
return self.question_text
class Choice(models.Model):
# ...
def __str__(self):
return self.choice.text編輯polls/models.py，add a custom method
import datetime
from django.db import models
from django.utils import timezone
class Question(models.Model):
# ...
def was_published_recently(self):
return self.pub_date >= timezome.now() - datetime.timedelta(days=1)保存這些更改並重新啓動一個新的Python交互式shell ：python manage.py shell
>>> from polls.models import Question, Choice
# Make sure our __str__() addition worked.
>>> Question.objects.all()
<QuerySet [<Question: What's up?>]>
# Django provides a rich database lookup API that's entirely driven by
# keyword arguments.
>>> Question.objects.filter(id=1)
<QuerySet [<Question: What's up?>]>
>>> Question.objects.filter(question_text__startswith='What')
<QuerySet [<Question: What's up?>]>
# Get the question that was published this year.
>>> from django.utils import timezone
>>> current_year = timezone.now().year
>>> Question.objects.get(pub_date__year=current_year)
<Question: What's up?>
# Request an ID that doesn't exist, this will raise an exception.
>>> Question.objects.get(id=2)
Traceback (most recent call last):
...
DoesNotExist: Question matching query does not exist.
# Lookup by a primary key is the most common case, so Django provides a
# shortcut for primary-key exact lookups.
# The following is identical to Question.objects.get(id=1).
>>> Question.objects.get(pk=1)
<Question: What's up?>
# Make sure our custom method worked.
>>> q = Question.objects.get(pk=1)
>>> q.was_published_recently()
True
# Give the Question a couple of Choices. The create call constructs a new
# Choice object, does the INSERT statement, adds the choice to the set
# of available choices and returns the new Choice object. Django creates
# a set to hold the "other side" of a ForeignKey relation
# (e.g. a question's choice) which can be accessed via the API.
>>> q = Question.objects.get(pk=1)
# Display any choices from the related object set -- none so far.
>>> q.choice_set.all()
<QuerySet []>
# Create three choices.
>>> q.choice_set.create(choice_text='Not much', votes=0)
<Choice: Not much>
>>> q.choice_set.create(choice_text='The sky', votes=0)
<Choice: The sky>
>>> c = q.choice_set.create(choice_text='Just hacking again', votes=0)
# Choice objects have API access to their related Question objects.
>>> c.question
<Question: What's up?>
# And vice versa: Question objects get access to Choice objects.
>>> q.choice_set.all()
<QuerySet [<Choice: Not much>, <Choice: The sky>, <Choice: Just hacking again>]>
>>> q.choice_set.count()
3
# The API automatically follows relationships as far as you need.
# Use double underscores to separate relationships.
# This works as many levels deep as you want; there's no limit.
# Find all Choices for any question whose pub_date is in this year
# (reusing the 'current_year' variable we created above).
>>> Choice.objects.filter(question__pub_date__year=current_year)
<QuerySet [<Choice: Not much>, <Choice: The sky>, <Choice: Just hacking again>]>
# Let's delete one of the choices. Use delete() for that.
>>> c = q.choice_set.filter(choice_text__startswith='Just hacking')
>>> c.delete()創建超級管理員
$ python manage.py createsuperuser
# 根據提示錄入Username|Password訪問 http://localhost:9000/admin/
Make the poll app modifiable in the admin
polls.py/admin.py
from django.contrib import admin
from .models import Question
admin.site.register(Question)重啓服務
$ python manage.py runserver訪問 http://localhost:9000/admin/
http://localhost:9000/admin/polls/question/add/
注意事項：
- 表單是從Question模型自動生成的。
- 不同的模型字段類型（DateTimeField， CharField）對應於適當的HTML輸入小部件。每種類型的字段知道如何在Django管理員中顯示自己。
- 每個都DateTimeField獲得免費的JavaScript快捷方式。日期獲取“今日”快捷方式和日曆彈出窗口，並且時間獲取“Now”快捷方式和一個方便的彈出窗口，列出常用的時間。
頁面底部提供了幾個選項：
- 保存 - 保存更改並返回到此類型對象的更改列表頁面。
- 保存並繼續編輯 - 保存更改並重新加載此對象的管理頁面。
- 保存並添加另一個 - 保存更改並加載此類型對象的新的空白表單。
- 刪除 - 顯示刪除確認頁面。
