学习笔记
一、创建一个服务器
需求：
1.熟悉操作命令
2.连接mysql数据库.
3.创建app=》polls
4.熟悉django的数据库操作命令
实践：
-
安装Django：
1.我用的是Mac版pycharm，所以直接用内置安装第三方工具安装的Django -
校验django是否安装成功
$ python -c "import django; print(django.get_version())" -
新建项目名：
django-admin startproject mysite注：报错找不到django-admin解决方案：向
/usr/local/bin/中添加软连接，也有可能是当前python路径没有执行权限sudo chmod +x django-admin.py软连接：
sudo ln -s /usr/local/python27/python_path/django-admin.py /usr/local/bin/django-admin.py -
设置TIME_ZONE:
TIME_ZONE ='Asia/Shanghai' -
使用Mysql数据库
- 在
mysite/settings.py中设置：
DATABASES = { 'default': { 'ENGINE': 'django.db.backends.mysql', 'NAME': 'db_wph', 'USER': 'root', 'PASSWORD': '123456', 'HOST': '127.0.0.1', 'PORT': '3306' } }-
然后使用命令：
$ python manage.py migrate
- 在
-
测试一下服务器是否搭建成功：
$ python manage.py runserverPerforming system checks... 0 errors found May 13, 2015 - 15:50:53 Django version 1.8, using settings 'mysite.settings' Starting development server at http://127.0.0.1:8000/ Quit the server with CONTROL-C.浏览器中输入网址：
http://127.0.0.1:8000/ -
按
control+c结束进程服务，并释放8000端口指定端口命令
$ python manage.py runserver 8080监听所有端口：
$ python manage.py runserver 0.0.0.0:8000 -
新建一个app=》polls
$ python manage.py startapp pollspolls/ __init__.py admin.py migrations/ __init__.py models.py tests.py views.py- 修改
polls/models.py
from django.db import models - 修改
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)
choice_text = models.CharField(max_length=200)
votes = models.IntegerField(default=0)
- 激活app,修改`mysite/settings.py`
INSTALLED_APPS = (
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'polls',
)
```
-
运行命令：
$ python manage.py makemigrations polls通过运行makemigrations告诉Django，已经对模型做了一些更改（在这个例子中，你创建了一个新的模型）并且会将这些更改存储为迁移文件。
-
运行迁移命令：
$ python manage.py sqlmigrate polls 0001-
再次运行migrate以在你的数据库中创建模型所对应的表：将这些改变更新到数据库中。
$ python manage.py migrate
-
-
进入mysql查看表结构
mysql> show tables; +----------------------------+ | Tables_in_db_wph | +----------------------------+ | auth_group | | auth_group_permissions | | auth_permission | | auth_user | | auth_user_groups | | auth_user_user_permissions | | city_list | | django_admin_log | | django_content_type | | django_migrations | | django_session | | polls_choice | | polls_question | | supplier | +----------------------------+ 14 rows in set (0.00 sec)
-
了解api命令 -操作数据库命令
- 进入shell
$ 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() [] # 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() [<Question: Question object>]
mysql> select * from polls_question; +----+---------------+----------------------------+ | id | question_text | pub_date | +----+---------------+----------------------------+ | 1 | what's up? | 2016-10-20 06:58:26.437937 | +----+---------------+----------------------------+mysql> select * from polls_choice; +----+--------------------+-------+-------------+ | id | choice_text | votes | question_id | +----+--------------------+-------+-------------+ | 1 | Not much | 0 | 1 | | 2 | The sky | 0 | 1 | +----+--------------------+-------+-------------+ 3 rows in set (0.00 sec)>>> from polls.models import Question, Choice # Make sure our __str__() addition worked. >>> Question.objects.all() [<Question: What's up?>] # Django provides a rich database lookup API that's entirely driven by # keyword arguments. >>> Question.objects.filter(id=1) [<Question: What's up?>] >>> Question.objects.filter(question_text__startswith='What') [<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() [] # 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() [<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) [<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()
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