django基础-CFANZ编程社区

文章目录

一、环境

1.1 Django安装:

二、创建Django工程

2.1 创建命令django-admin startproject xuegod
2.2 运行命令python manage.py runserver
2.3 浏览器打开http://127.0.0.1:8000/

三、知识点

3.1 MVC MTV开发模式
3.2 个人理解:
3.3 views.py, 创建浏览器视图
3.4 urls网页请求
3.5 浏览器打开 127.0.0.1:8000/index

问题出现的问题是: No module named 'views'

3.6 template文件夹创建显示魔板
3.7 变量,标签,条件,循环

条件`{% if name %}{% else %}{% endif %}`
变量 `{{name}}`
循环`{% for index in test_list %}{{index }}{%endfor%}`

四、新建工程,创建模型层APP,与mysql通信

4.1 创建工程django-admin startproject mysql_project
4.2 测试

a 创建文件夹template,修改settings.py`os.path.join(BASE_DIR, "template".replace("\\",'/'))`
b 在 template文件夹中创建index.html
c 创建mysql_project/views_test.py
d 在mysql_project/urls.py中调用
e 打开服务器,浏览器

4.3 创建APP User`python manage.py startapp User`
4.4 编辑User/models.py, `class User(models.Model)`
4.5 修改mysql_project/settings.py
4.6 数据库操作
4.7 同步数据库

a 检测数据库配置`python manage.py validate`
b 同步数据 `python manage.py makemigrations`
c 同步数据库表`python manage.py syncdb`

4.8 Django对数据库的增查

a 命令行插入数据`python manage.py shell`
b Django显示数据

修改User/views.py
创建template/user.html
修改ursl.py文件
浏览器显示

4.9 Django对数据库的删改

a 命令行删除和修改数据`python manage.py shell

修改u.name = "FOR"; u.save()
删除u.delete()

一、环境

win10 python3.6 Django 1.8.2 sublime TXT

1.1 Django安装:

pip install django==1.8.2 -i https://pypi.mirrors.ustc.edu.cn/simple/
apt-get install python-mysqldb
# 上面出错的话执行下面命令
sudo apt-get install python-dev

二、创建Django工程

2.1 创建命令django-admin startproject xuegod

2.2 运行命令python manage.py runserver

2.3 浏览器打开http://127.0.0.1:8000/

三、知识点

3.1 MVC MTV开发模式

MVC模式
M模型 数据库,完成数据表的建立orm, 映射到数据库
V视图 放在服务器上用来处理用户请求的东西
C控制器 控制视图由谁显示

MTV 模式
模式  存在数据
T template 指定显示方式 前端
V views 指定显示数据

3.2 个人理解:

Django是Python框架, 用于创建前端后端的统一的框架, 客户端请求,服务器响应, 
调出数据库后端, 返回数据, 前端浏览器进行显示

3.3 views.py, 创建浏览器视图

# 在包里面新建views.py,用于视图
# 
# HTTP重要的两个元素
# request:请求(客户)
# response:响应(服务器)

django基础_html

# views.py
from django.http import HttpResponse
def index(request):
  return HttpResponse("hello world")
  pass

3.4 urls网页请求

from django.conf.urls import include, url
from django.contrib import admin
# from . import views
import views

urlpatterns = [
    url(r'^admin/', include(admin.site.urls)),
    url(r'^index',views.index), # 这里应为新建的views.index包含的函数是返回hello world
]

3.5 浏览器打开 127.0.0.1:8000/index

问题出现的问题是: No module named ‘views’

django基础_html_02

解决方案: 修改import views为from . import views 在运行127.0.0.1:8000/index成功显示为

django基础_html_03

3.6 template文件夹创建显示魔板

django基础_python_04

说明: template文件放置html页面显示魔板

在settings.py里面修改配置添加template

django基础_python_05

os.path.join(BASE_DIR, "template".replace("\\",'/')) 表示根路径下链接template, 即D:\NodeAndCode\0_python3\Django\project_test\xuegod\template,在将\转换为/

# views.py
from django.http import HttpResponse
from django.template.loader import get_template # 加载魔板
from django.template import Context  # 进行数据传输
from django.shortcuts import render_to_response  # 进行数据传输

def index(request):
  return HttpResponse("hello world")
  pass

def birthday(request, day):
  years = 2017-int(day)
  return HttpResponse("you are %s"%years)

def happy(request):
  template = get_template("index.html")
  context = Context({"name":"jjjjj", "age":18,}) # 对返回的内容进行封装
  return HttpResponse(template.render(context))
  pass

def fun(request):
  # return render_to_response("index.html",{"name":"fofo", "age":18,})
  name = "fofo"
  age = 18
  return render_to_response("index.html", locals()) 
  # locals将会把函数内的所有变量传到前端
  pass

# urls.py
from django.conf.urls import include, url
from django.contrib import admin

from . import views

urlpatterns = [
    url(r'^admin/', include(admin.site.urls)),
    url(r'^index/$', views.index), # 调用的使用127.0.0.1:8000/index
    url(r'^birthday/(\d{4})/$', views.birthday), # 调用的使用127.0.0.1:8000/birthday/1990
    url(r'^happy', views.happy),
    url(r'^fun', views.fun)
]

# index.html
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>index_test_zjq</title>
</head>
  <body>
    <p>注意是双大括号</p>
    <p style="color:red; font-size:24px">
      i am {{name}} a python ,hello world today is {{age}} 
    </p>
  </body>
</html>

说明:
首先在浏览器输入127.0.0.1:8000/urls.py里面的那几个请求,
服务器就会根据请求从url(r'^网页字符匹配', 匹配函数地址)去views.py寻找对应的函数执行, 而views.py内的函数调用并传递参数给html(template魔板), 以此来显示html魔板

3.7 变量,标签,条件,循环

条件{% if name %}{% else %}{% endif %}

变量 {{name}}

循环{% for index in test_list %}{{index }}{%endfor%}

看代码, 在重申一遍, urls.py调用views.py, views.py调用html文件显示前端

<!-- if_for.html -->
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>变量</title>
</head>
  <body>
        <P>hello</P>
        <!-- if else endif -->
        <P>
            {% if name %}
            <p>have name {{name}}</p>

            {% else %}
            <p>no name</p>
            {% endif %}
        </P>
        <!-- ifequal endifequal-->
        <p>
            {% ifequal name "zjq" %}
            <P>ifequal 如果等于 name "zjq"</P>
            {% else %}
            <p>else的操作name!=zjq {{name}}</p>
            {% endifequal %}

        </p>
        <!-- for endfor -->
        <p>
            {% for index in test_list %}
                <h1>{{index}} forloop就是每个元素的监控 {{forloop}} forloop.last {{forloop.last}}</h1>
            {%endfor%}
        </p>

        <!-- for forloop endfor -->
        <p>
            <h1>hello</h1>
            {% for index in c_list %}
                {%if forloop.last%}
                    <h1 style="color: blue;">{{index}}</h1>
                {% else %}
                    <h1 style="color: red;">{{index}}</h1>
                {%endif%}
            {% endfor %}

            <h1>过滤器 {{name|upper}}</h1>
        </p>

  </body>
</html>

注意: `render_to_response("if_for.html",locals())`表示将当前函数内的所有参数都传递到if_for.html文件内

# views.py
# coding:utf-8
from django.http import HttpResponse
from django.template.loader import get_template # 加载魔板
from django.template import Context  # 进行数据传输
from django.shortcuts import render_to_response  # 进行数据传输

# if for测试
def if_for(request):
  # print
  test_list = ["a", "b", "c"] # 列表索引测试
  name = "mzjq"
  c_list = range(3)
  return render_to_response("if_for.html",locals())

# urls.py
from django.conf.urls import include, url
from django.contrib import admin
from . import views

urlpatterns = [
    url(r'^admin/', include(admin.site.urls)),
    url(r'^if_for', views.if_for),
]

浏览器输入 127.0.0.1:8000/if_for

django基础_django_06

四、新建工程,创建模型层APP,与mysql通信

4.1 创建工程django-admin startproject mysql_project

django基础_html_07

4.2 测试

下面的所有代码的程序工程文件 mysql_project.rar

a 创建文件夹template,修改settings.py`os.path.join(BASE_DIR, "template".replace("\\",'/'))`

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [
            os.path.join(BASE_DIR, "template".replace("\\",'/')), # 添加的template路径
        ],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

b 在 template文件夹中创建index.html

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>index_test_zjq</title>
</head>
  <body>
    <p>注意是双大括号</p>
    <p style="color:red; font-size:24px">
      i am {{name}} a python ,hello world today is {{age}} 
    </p>
    <p>字典参数显示:{{content}}, 或者{{content.name}}, 还可以调用字符串的内部方法{{content.name.upper}}</p>
    <p>类的参数显示: {{pc}}, 独立参数{{pc.hp}} 独立方法{{pc.fight}} 然后结果是{{pc.hp}} </p>
    <p>列表索引格式test_list.1 = {{test_list.1}}</p>
  </body>
</html>

c 创建mysql_project/views_test.py

from django.shortcuts import render_to_response  # 进行数据传输

class Hero:
  def __init__(self):
    self.hp = 100
    self.mp = 100
  def fight(self):
    self.hp -= 10
def index(request):
  name = "fun2"
  content = {"name":"hello", "age":18} # 字典测试
  pc = Hero() #类实例化参数测试
  test_list = ["a", "b", "c"] # 列表索引测试
  return render_to_response("index.html", locals())

d 在mysql_project/urls.py中调用

# urls.py
from django.conf.urls import include, url
from django.contrib import admin
from . import views_test

urlpatterns = [
    url(r'^admin/', include(admin.site.urls)),
    url(r'^index/$', views_test.index), # 调用的使用127.0.0.1:8000/index
]

e 打开服务器,浏览器

django基础_django_08

4.3 创建APP User`python manage.py startapp User`

django基础_python_09

此时文件夹应该包含如下

django基础_python_10

4.4 编辑User/models.py, `class User(models.Model)`

from django.db import models
# Create your views here.
class User(models.Model):
    name  = models.CharField(max_length=32)
    age   = models.IntegerField()
    email = models.EmailField(max_length=32)
    # 注意两点
    # 映射层字段默认都是不为空
    # 默认有主键id

4.5 修改mysql_project/settings.py

以下模块内数据需要修改

# 修改1
DATABASES = {
    'default': {
        # 默认数据库
        # 'ENGINE': 'django.db.backends.sqlite3',
        # 'NAME': os.path.join(BASE_DIR, 'db.sqlite3'), 
        # zjq 配置mysql
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'Django', # 注意这个数据库通过root用户需要新建
        'HOST':'localhost', 
        'USER':'root', 
        'PASSWORD':'zjq',
        'PORT':3306, # 默认不用加
    }
}

# 修改2 
INSTALLED_APPS = (
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'User', # zjq添加 刚刚创建app的名字 
)

4.6 数据库操作

登陆数据库
PS C:\Users\Admin_Q> mysql -u root -p 
Enter password: ***

#创建数据库
mysql> create databases Django;
Query OK, 1 row affected (0.01 sec)

4.7 同步数据库

a 检测数据库配置`python manage.py validate`

$ python manage.py validate
D:\ProgramFiles\python3.6.8\lib\site-packages\django\core\management\commands\validate.py:15: RemovedInDjango19Warning: "validate" has been deprecated in favor of "check".
  RemovedInDjango19Warning)

System check identified no issues (0 silenced).

b 同步数据 `python manage.py makemigrations`

$ python manage.py makemigrations
Migrations for 'User':
  0001_initial.py:
    - Create model User

此时 User/migrations/0001_initial.py的内容

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.db import models, migrations


class Migration(migrations.Migration):

    dependencies = [
    ]

    operations = [
        migrations.CreateModel(
            name='User',
            fields=[
                ('id', models.AutoField(verbose_name='ID', primary_key=True, serialize=False, auto_created=True)),
                ('name', models.CharField(max_length=32)),
                ('age', models.IntegerField()),
                ('email', models.EmailField(max_length=32)),
            ],
        ),
    ]

遇到的问题: No changes detected in app 'User 说明:如果严格按照上面的操作是不会有次问题的
我出错的原因是因为,将class User()定义到了User/views.py中了,其实应该定义到User/models.py中

另外看网上出现此问题的另外很多原因总结如下:

在class User()定义时没有继承类Models,应该注意 class User(models.Model):
当出现No changes detected时,尝试网上一种方案: python manage.py makemigrations --empty APPname,但是这个虽然运行没有问题,也生成了0001_initial.py,但是此py非彼py,所以此方案有待考究
在settings.py中忘记注册User,也就是INSTALLED_APPS = ('User',)
综上所述, 除了马虎大意,其他高端题似乎还没有.

c 同步数据库表`python manage.py syncdb`

$ python manage.py syncdb
D:\ProgramFiles\python3.6.8\lib\site-packages\django\core\management\commands\syncdb.py:24: RemovedInDjango19Warning: The syncdb command will be removed in Django 1.9
  warnings.warn("The syncdb command will be removed in Django 1.9", RemovedInDjango19Warning)

Operations to perform:
  Synchronize unmigrated apps: staticfiles, messages
  Apply all migrations: contenttypes, User, auth, admin, sessions
Synchronizing apps without migrations:
  Creating tables...
    Running deferred SQL...
  Installing custom SQL...
Running migrations:
  Rendering model states... DONE
  Applying User.0001_initial... OK
  Applying contenttypes.0001_initial... OK
  Applying auth.0001_initial... OK
  Applying admin.0001_initial... OK
  Applying contenttypes.0002_remove_content_type_name... OK
  Applying auth.0002_alter_permission_name_max_length... OK
  Applying auth.0003_alter_user_email_max_length... OK
  Applying auth.0004_alter_user_username_opts... OK
  Applying auth.0005_alter_user_last_login_null... OK
  Applying auth.0006_require_contenttypes_0002... OK
  Applying sessions.0001_initial... OK

You have installed Django's auth system, and don't have any superusers defined.
Would you like to create one now? (yes/no): yes
Username (leave blank to use 'admin_q'): admin
Email address: xxx@qq.com
Password:
Password (again):
Superuser created successfully.

此时数据库表已经更新成为我们刚刚在class里面定义的三个参数

mysql> use Django;
Database changed
mysql> show tables;
+----------------------------+
| Tables_in_django           |
+----------------------------+
| auth_group                 |
| auth_group_permissions     |
| auth_permission            |
| auth_user                  |
| auth_user_groups           |
| auth_user_user_permissions |
| django_admin_log           |
| django_content_type        |
| django_migrations          |
| django_session             |
| user_user                  |
+----------------------------+
11 rows in set (0.00 sec)
mysql> desc user_user;
+-------+-------------+------+-----+---------+----------------+
| Field | Type        | Null | Key | Default | Extra          |
+-------+-------------+------+-----+---------+----------------+
| id    | int(11)     | NO   | PRI | NULL    | auto_increment |
| name  | varchar(32) | NO   |     | NULL    |                |
| age   | int(11)     | NO   |     | NULL    |                |
| email | varchar(32) | NO   |     | NULL    |                |
+-------+-------------+------+-----+---------+----------------+
4 rows in set (0.01 sec)

4.8 Django对数据库的增查

	mysql	Django
增	inset	instace.objects.create
删	drop	delete
改	update/alter	update
查	select	instace.objects.all
		instace.objects.filter
		instace.objects.get
		instace.objects.order_by
		instace.objects.create

from User.models import User # 导入User表

a 命令行插入数据`python manage.py shell`

命令行操作

Admin_Q@DESKTOP-AKFGQ25 MINGW64 /d/NodeAndCode/0_python3/Django/mysql_project
$ python manage.py shell
Python 3.6.8 (tags/v3.6.8:3c6b436a57, Dec 24 2018, 00:16:47) [MSC v.1916 64 bit (AMD64)]
Type 'copyright', 'credits' or 'license' for more information
IPython 7.8.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: print("hello")
hello

In [2]: from User.models import User

In [3]: u = User(name="for", age = 21, email= "for@qq.com")

In [4]: u.save()

In [5]: User.objects.create(name="while",age=22.email="while@qq.com")
  File "<ipython-input-5-a39842fb466e>", line 1
    User.objects.create(name="while",age=22.email="while@qq.com")
                                                ^
SyntaxError: invalid syntax


In [6]: User.objects.create(name="while", age = 21, email= "while@qq.com")
Out[6]: <User: User object>

In [7]: User.objects.create(name="make", age = 43, email= "make@qq.com")
Out[7]: <User: User object>

In [8]: User.objects.create(name="jk", age = 29, email= "jk@qq.com")
Out[8]: <User: User object>

In [9]: User.objects.create(name="okp", age = 14, email= "okp@qq.com")
Out[9]: <User: User object>

数据库中数据显示
mysql> select * from user_user;
+----+-------+-----+--------------+
| id | name  | age | email        |
+----+-------+-----+--------------+
|  1 | for   |  21 | for@qq.com   |
|  2 | while |  21 | while@qq.com |
+----+-------+-----+--------------+
2 rows in set (0.00 sec)

b Django显示数据

修改User/views.py

from django.shortcuts import render_to_response
from .models import User

# Create your views here.
def user(request):
    name = "user_zjq"
    age = 32

    all_user_data = User.objects.all()  # select * from user_user

    filter_user = User.objects.filter(name="while") #筛选 select * from user_user where  name="while"

    # 记住.get这个不能乱用,不然会出错
    # get_user = User.objects.get(id=1)  # get条件必须唯一, 通常为主键

    order_user = User.objects.order_by("age") # 排序输出, 按照年龄进行排序输出
    order_user_front2 = User.objects.order_by("age")[:2] # 排序输出取前两个

    fo_user = User.objects.filter(age=21).order_by("name")  # 首先取出age=21的,然后在按照name排序
    

    return render_to_response("user.html", locals())

问题: 无法显示, 使用VCcode总是显示 Class 'User' has no 'objects' memberpylint(no-member)
于是对于User导入包的方式各种尝试
from User.models import User
from .models import User
sys.path.append(r"../User/") from User.models import User
以上都有问题,于是我就不管错误, 直接在网页操作, 发现网页按照预期进行显示(上面两种导入方式)
建议使用第二种导入方式, .models表示导入当前包中的文件models.py

创建template/user.html

<!DOCTYPE html>
<html>
<head>
  <title>user</title>
  <meta charset="utf-8">
</head>
  <body>
        <h1>this is user page this name is {{name}}, {{age}} years old</h1>
        <h1>select * from user_user</h1>
        <ul>
            {% for i in all_user_data %}
            <li>
                {{i.name}} {{i.age}} {{i.email}}
            </li>
            {% endfor %}
        </ul>


        <h1>select * from user_user where  name="while"</h1>
        <u1>
            {% for i in filter_user %}
            <li>
                {{i.name}} {{i.age}} {{i.email}}
            </li>
            {% endfor %}
        </u1>

        <h1>s按照age排序从大到小排序</h1>
        <u1>
            {% for i in order_user %}
            <li>
                {{i.name}} {{i.age}} {{i.email}}
            </li>
            {% endfor %}
        </u1>

        <h1>select * from user_user where  id=1, 但是get不是列表格式,而是一条数据</h1>
        <u1>
            <l1>{{get_user.name}},{{get_user.age}},{{get_user.email}}</l1> 
        </u1>
  </body>
</html>

修改ursl.py文件

# urls.py
from django.conf.urls import include, url
from django.contrib import admin
from . import views_test
from User.views import *


urlpatterns = [
    url(r'^admin/$', include(admin.site.urls)),
    url(r'^index/$', views_test.index), # 调用的使用127.0.0.1:8000/index
    url(r"^user/$", user)
]

浏览器显示

django基础_html_11

4.9 Django对数据库的删改

a 命令行删除和修改数据`python manage.py shell

修改u.name = “FOR”; u.save()

删除u.delete()

Admin_Q@DESKTOP-AKFGQ25 MINGW64 /d/NodeAndCode/0_python3/Django/mysql_project
$ python manage.py shell
Python 3.6.8 (tags/v3.6.8:3c6b436a57, Dec 24 2018, 00:16:47) [MSC v.1916 64 bit (AMD64)]
Type 'copyright', 'credits' or 'license' for more information
IPython 7.8.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: print("hello")
hello

In [2]: from User.models import User

In [3]: u = User(name="for", age = 21, email= "for@qq.com")

In [4]: u.save()

In [5]: User.objects.create(name="while",age=22.email="while@qq.com")
  File "<ipython-input-5-a39842fb466e>", line 1
    User.objects.create(name="while",age=22.email="while@qq.com")
                                                ^
SyntaxError: invalid syntax


In [6]: User.objects.create(name="while", age = 21, email= "while@qq.com")
Out[6]: <User: User object>

In [7]: User.objects.create(name="make", age = 43, email= "make@qq.com")
Out[7]: <User: User object>

In [8]: User.objects.create(name="jk", age = 29, email= "jk@qq.com")
Out[8]: <User: User object>

In [9]: User.objects.create(name="okp", age = 14, email= "okp@qq.com")
Out[9]: <User: User object>

# 修改id=1的name数据为大写
In [10]: u = User.objects.get(id=1)

In [11]: u.name
Out[11]: 'for'

In [12]: u.name = "FOR"

In [13]: u.save()

In [14]: u.name
Out[14]: 'FOR'
# 删除id=1的数据
In [15]: u = User.objects.get(id=1)

In [16]: u.delete()

修改name
mysql> select * from user_user;
+----+-------+-----+--------------+
| id | name  | age | email        |
+----+-------+-----+--------------+
|  1 | FOR   |  21 | for@qq.com   |
|  2 | while |  21 | while@qq.com |
|  3 | make  |  43 | make@qq.com  |
|  4 | jk    |  29 | jk@qq.com    |
|  5 | okp   |  14 | okp@qq.com   |
+----+-------+-----+--------------+
5 rows in set (0.00 sec)

删除id=1
mysql> select * from user_user;
+----+-------+-----+--------------+
| id | name  | age | email        |
+----+-------+-----+--------------+
|  2 | while |  21 | while@qq.com |
|  3 | make  |  43 | make@qq.com  |
|  4 | jk    |  29 | jk@qq.com    |
|  5 | okp   |  14 | okp@qq.com   |
+----+-------+-----+--------------+
4 rows in set (0.00 sec)

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