django 实战(11): 自定义Lecture模型（与Teacher模型多对一关系）

1 创建应用lecture

(base) xxx@xxx-virtual-machine:~/AuthDemo$ django-admin startapp lecture

(base) xxx@xxx-virtual-machine:~/AuthDemo$

1.1 在应用lecture的目录下创建文件和文件夹

    新建模板目录templates、templatetags，
    新建文件forms.py、urls.py
    在模板目录templates下，创建与应用名同名的子目录

1.2 在settings.py中注册应用

    INSTALLED_APPS = [
        "django.contrib.admin",
        "django.contrib.auth",
        "django.contrib.contenttypes",
        "django.contrib.sessions",
        "django.contrib.messages",
        "django.contrib.staticfiles",
        "basedata",
        "users",

        "student",

        "teacher",

        "lecture",

    ]

2 在lecture/models.py中定义讲座模型Lecture

Teacher模型与Lecture模型一对多关系，外键定义在Lecture模型内

from django.db import models

# Create your models here.

from teacher.models import Teacher

# 讲座模型与Teacher是多对一的关系

class Lecture(models.Model):

# 如果删除了老师，关联的讲座也会被删除

lectureTeacher = models.ForeignKey(Teacher,on_delete=models.CASCADE)

name = models.CharField(max_length=256, null=False) # 讲座名称

address = models.CharField(max_length=256) # 讲座地点

start_time = models.DateTimeField(null=True) # 讲座开始时间

status = models.BooleanField(default=True) # 讲座状态

limits = models.IntegerField(default=1000) # 讲座限制人数

# 覆盖对象对外的字符串表现形式

def __str__(self):

return self.name

2.1 数据迁移

    (base) xxx@xxx-virtual-machine:~/AuthDemo$ python manage.py makemigrations

    Migrations for 'teacher':

      teacher/migrations/0001_initial.py

        - Create model Teacher

    (base) xxx@xxx-virtual-machine:~/AuthDemo$ python manage.py migrate lecture

    Operations to perform:

      Apply all migrations: teacher

    Running migrations:

      Applying teacher.0001_initial... OK

    (base) xxx@xxx-virtual-machine:~/AuthDemo$

3 在lecture/forms.py中，定义表单

LectureAddForm、LectureUpdateForm两张表单一摸一样，只是字段名称不一样。这是因为这两张表单要用在同一个页面中。所以每个输入框的id不能一样。LectureUpdateForm在每个字段名称后面加上了U。

from lecture.models import Lecture

class LectureAddForm(forms.Form):

name = forms.fields.CharField( #要填入Lecture模型中的字段

label = '讲座名称',

required =True,

min_length = 2,

max_length = 256,

error_messages={

"required":"讲座名称不可以为空！",

"min_length":"讲座名称不能低于2位！",

"max_length":"讲座名称不能超过256位！"

}

)

address = forms.fields.CharField(

label = '讲座地点',

required =True,

min_length = 4,

max_length = 256,

error_messages={

"required":"讲座地点不可以为空！",

"min_length":"讲座地点不能低于4位！",

"max_length":"讲座地点不能超过256位！"

}

)

start_time = forms.fields.CharField(

label = '开始时间',

required =True,

min_length = 18,

max_length = 19,

error_messages={

"required":"开始时间不可以为空！",

"min_length":"开始时间格式为yyyy-mm-dd hh:mm:ss不能低于18位！",

"max_length":"开始时间格式为yyyy-mm-dd hh:mm:ss不能高于19位！"

}

)

status = forms.fields.BooleanField(

label = '讲座状态',

required =False,

)

limits = forms.fields.IntegerField(

label = '限制人数',

required =True,

initial=1000,

error_messages={

"required":"限制人数不可以为空！",

}

)

lectureTeacher = forms.fields.ChoiceField(

label = '讲座老师',

required =True,

error_messages={

"required":"必须选择一个讲座老师！",

}

)

class LectureUpdateForm(forms.Form):

nameU = forms.fields.CharField( #要填入Lecture模型中的字段

label = '讲座名称',

required =True,

min_length = 2,

max_length = 256,

error_messages={

"required":"讲座名称不可以为空！",

"min_length":"讲座名称不能低于2位！",

"max_length":"讲座名称不能超过256位！"

}

)

addressU = forms.fields.CharField(

label = '讲座地点',

required =True,

min_length = 4,

max_length = 256,

error_messages={

"required":"讲座地点不可以为空！",

"min_length":"讲座地点不能低于4位！",

"max_length":"讲座地点不能超过256位！"

}

)

start_timeU = forms.fields.CharField(

label = '开始时间',

required =True,

min_length = 18,

max_length = 19,

error_messages={

"required":"开始时间不可以为空！",

"min_length":"开始时间格式为yyyy-mm-dd hh:mm:ss不能低于18位！",

"max_length":"开始时间格式为yyyy-mm-dd hh:mm:ss不能高于19位！"

}

)

statusU = forms.fields.BooleanField(

label = '讲座状态',

required =False,

)

limitsU = forms.fields.IntegerField(

label = '限制人数',

required =True,

initial=1000,

error_messages={

"required":"限制人数不可以为空！",

}

)

lectureTeacherU = forms.fields.ChoiceField(

label = '讲座老师',

required =True,

error_messages={

"required":"必须选择一个讲座老师！",

}

)

4 在lecture/views.py中定义视图函数query、add、update、delete

add()、update()函数存在添加，修改失败的问题；需要将信息传递到上述两个函数重定向到的query()函数中。详细说明在代码中有：

重定向传值是通过session来进行的。

详细代码如下：

from django.shortcuts import render,redirect

# Create your views here.

from lecture.models import Lecture

from teacher.models import Teacher

from lecture.forms import LectureAddForm,LectureUpdateForm

from django.core.paginator import Paginator

# 导入获取自定义User对象的方法

from django.contrib.auth import get_user_model

User = get_user_model() # 获取自定义User模型

##########################################

# Lecture 、Teacher的操作 (多对一) #

##########################################

# 分页查询所有指向数据库操作的主页面teacher.html

def query(request,per_page='2',current_page='1'):

''''

功能：分页函数。

若是查询所有，进行分页。若是模糊查询，不分页。

参数: per_page: 每页记录数, 默认值是'2'.

current_page: 当前页, 默认值是'1', 即首页

request.POST[name]: 模糊查询的条件

返回值: 一个字典。字典中的key含义如下:

'count': 查询结果总记录数。 int

'count_all': 数据表中总记录数。 int

若count == count_all,就是全部查询

'per_page': 每页记录数。 int

'num_pages': 页面总数。 int

'current_page': 当前页面数。 int

'page_bar_range':分页栏显示的数字范围。list

'result': 若不是模糊查询，当前页面数对应的结果。querySet

若是模糊查询,不分页,模糊查询的所有结果。querySet

'form': Lecture的新增表单

'formU': Lecture的修改表单

'search_name': 查询条件。供页面刷新时<input>显示最近一次输入值用

'app_name': 应用名称。

'id': 页面选择状态

'teacherList': <select>元素的<option>选项表

'code': add()、update()函数的状态码

'message': add()、update()函数的信息

'errorInfo': add()、update()函数的错误原因

'''

# 初始化返回值为空的字典

context = {}

# 读取add()、update()函数设置的session,若没有，则为None

context['code'] = request.session.get('code')

context['message'] = request.session.get('message')

context['errorINFO'] = request.session.get('errorINFO')

#删除由add()、update()函数设置的session

if request.session.get('code') != None:

request.session.pop('code')

request.session.pop('message')

request.session.pop('errorINFO')

# 读取update()函数设置的页面，若没有，则为None

id ='0' #应为路由不传id值，所以设置一个

if request.session.get('per_page') != None:

# 读取session

per_page = int(request.session['per_page'])

current_page = int(request.session['current_page'])

id = int(request.session['id'])

#删除session

request.session.pop('per_page')

request.session.pop('current_page')

request.session.pop('id')

else: #没有session,则是路由传值，或初始值

#因为路由传值、初始值都是字符串，所以需要转换为整数

per_page = int(per_page)

current_page = int(current_page)

id = int(id)

# 获取数据，按id排序

varList = ''

if request.POST : # 模糊查询

varList = Lecture.objects.filter(name__contains = request.POST['search_name']).order_by('start_time')

# 保存查询条件，供index.html页面要设置搜索栏表单中的相应输入框value属性用

context['search_name'] = request.POST['search_name']

else: # 查询所有

context['search_name'] = ''

varList = Lecture.objects.all().order_by('start_time')

# 创建分页器实例

paginator = Paginator(varList,per_page)

page = paginator.get_page(current_page)

# 设置在前端分页器栏为Bootstrap分页器内固定显示7页的参数

page_bar_range = range(1,8)

if paginator.num_pages > 7:

if current_page-3 < 1:

#当页面输入前三页时，使其分页器只显示前7页不变

page_bar_range = range(1,8)

elif current_page+3 > paginator.num_pages:

#当页面处于最后三页时，使分页器只显示最后固定7页

page_bar_range = range(paginator.num_pages-6,paginator.num_pages+1)

else:

page_bar_range = range(current_page-3,current_page+4)

else:

page_bar_range = paginator.page_range

context['page_bar_range'] = page_bar_range

context['count'] = paginator.count

context['count_all'] = Lecture.objects.all().count();

context['per_page'] = per_page

context['current_page'] = current_page

context['num_pages'] = paginator.num_pages

context['id'] = id

# 如果不是模糊查询，则分页；如果是，则不分页

if context['count'] == context['count_all']:

context['result'] = page

else:

context['result'] = varList

'''

将所有有关修改、新增所需要的基础数据列表传入前端

供前端<select>的<option>选项使用

'''

context['teacherList'] = querySetToList(Teacher.objects.all().order_by('id').values('id','name'))

context['form'] = LectureAddForm() #新增讲座用到的空表格

context['formU'] = LectureUpdateForm() #修改讲座用到的空表格

context['app_name'] = 'lecture'

return render(request, "index.html", context)

def querySetToList(querySet):

'''将querySet对象，转化为列表对象'''

varList =[]

for var in querySet:

varList.append( var)

return varList

def add(request):

# 1 处理POST请求

name=request.POST['name']

address=request.POST['address']

start_time = request.POST['start_time']

'''

模型中定义的status是Boolean类型

在定义表单相应的form时，该输入变成了type='checkbox'的<input>框。

status在前端反映的是输入类型checkbox的状态，勾选为true

不勾选则在request.POST中不存在这个键，所以不能直接用

request.POST['status']

而应该改用：

request.POST.get('status')

但传到后端来，变成了，勾选是on

不符合模型定义，尽管通过了表单清洗，还需要再清洗

'''

status = ''

if request.POST.get('status') == 'on':

status = True

else:

status = False

limits = request.POST['limits']

lectureTeacher_id = request.POST['lectureTeacher']

# 2 判断讲座名是否已经存在？

name_exists = Lecture.objects.filter(name= name).exists()

if name_exists: #如果讲座名称已经存在

# # 设置session, 操作状态

request.session['code'] = 400

request.session['message'] = '讲座添加失败'

request.session['errorINFO'] = "您输入的讲座名称已存在!"

print("您输入的讲座名称已存在!")

return redirect("/lecture/query")

# 3 保存到Lecture数据库

Lecture(

name=name,

address=address,

start_time = start_time,

status = status,

limits = limits,

lectureTeacher_id = lectureTeacher_id,

).save()

# 4 设置session

request.session['code'] = 200

request.session['message'] = '讲座添加成功'

request.session['errorINFO'] = ''

return redirect("/lecture/query/")

def update(request):

# 1 处理POST请求

id = request.POST['id']

current_page = request.POST["current_page"]

per_page = request.POST["per_page"]

name=request.POST['nameU']

address=request.POST['addressU']

start_time = request.POST['start_timeU']

status = ''

if request.POST.get('statusU') == 'on':

status = True

else:

status = False

limits = request.POST['limitsU']

lectureTeacher_id = request.POST['lectureTeacherU']

# 2 设置页面状态session

request.session['current_page'] = current_page

request.session['per_page'] = per_page

request.session['id'] = id

# 3 根据id 查询修改前的User信息

lectureBeforUpdate = Lecture.objects.get(id = id)

# 4 判定讲座名称是否已经存在

name_exists = Lecture.objects.filter(name= name).exists()

if (name_exists) and (name !=lectureBeforUpdate.name ):#如果讲座名称已经存在，并且与修改前的不一致

# 设置session, 操作状态

request.session['code'] = 400

request.session['message'] = '讲座修改失败'

request.session['errorINFO'] = "您输入的讲座名称已存在!"

print("您输入的讲座名称已存在!")

return redirect("/lecture/query")

# 5 保存到Lecture数据库

Lecture.objects.filter(id= id).update(

name=name,

address=address,

start_time = start_time,

status = status,

limits = limits,

lectureTeacher_id = lectureTeacher_id,

)

# 6 设置session

# 操作状态

request.session['code'] = 200

request.session['message'] = '讲座修改成功'

request.session['errorINFO'] = ''

# 页面状态

request.session['current_page'] = current_page

request.session['per_page'] = per_page

request.session['id'] = id

return redirect("/lecture/query/")

def delete(request):

# 1 将前端传过来的idList字符串分割为数组

idList=request.POST['idList'].split(' ')

# 2 逐一删除表中数据

for var in idList: # 删除从表

Lecture.objects.filter(id=int(var)).delete()

return redirect("/lecture/query")

5 模板文件

除了lecture/module_query.html之外，其他的都可以用第9节的模板文件。

<table id='table' class="table table-striped text-info">

<thead>

<tr>

<td><input id="allChecked" type="checkbox"></td>

<th><h4>ID</h4></th>

<th><h4>讲座名称</h4></th>

<th><h4>讲座地点</h4></th>

<th><h4>开始时间</h4></th>

<th><h4>状态</h4></th>

<th><h4>限制人数</h4></th>

<th><h4>主讲老师</h4></th>

<th><h4>操作</h4></th>

</tr>

</thead>

<tbody>

{% for var in result %}

<tr>

<td><input class="checked" type="checkbox"></td>

<td class="id"> <h5>{{var.id}}</h5></td>

<td> <h5>{{var.name}}</h5></td>

<td> <h5>{{var.address}}</h5></td>



<td class="start_time"> <h5>{{var.start_time|date:"Y-m-d H:i"}}</h5></td>

<td class="status"> <h5>{{var.status}}</h5></td>

<td class="limits"> <h5>{{var.limits}}</h5></td>

<td class="lectureTeacher"> <h5>{{var.lectureTeacher}}</h5></td>

<td class="edit">



<button type="button" class="update" data-toggle="modal" data-target="#module_updateModal" disabled="disabled">

<i class="fa-regular fa-pen-to-square"></i>

</button>



<button type="button" class="delete" data-toggle="modal" data-target="#module_deleteModal" disabled="disabled">

<i class="fa-solid fa-trash-can"></i>

</button>

</td>

</tr>

{% endfor %}

</tbody>

</table>

6 在lecture/urls.py中定义子路由

    from django.urls import path,re_path

    from . import views as view

    # 子路由列表

    urlpatterns = [

      path('query/', view.query, name='query-url'), # 分页查询

      re_path(r'^query/(?P<per_page>\d+)/(?P<current_page>\d+)/$',view.query), #传值路由

      path('add/',   view.add,    name='add-url'),     # 新增

      path('update/',view.update, name='update-url'), # 修改

      path('delete/',view.delete, name='delete-url'), # 删除

    ]

7 在AuthDemo/urls.py中管理子路由

    from django.contrib import admin
    from django.urls import path,include

    urlpatterns = [
      path("admin/", admin.site.urls),
      path('basedata/',include(('basedata.urls','basedata'))),
      path('student/', include(('student.urls', 'student'))),

      path('teacher/', include(('teacher.urls', 'teacher'))),

    path('lecture/', include(('lecture.urls', 'lecture'))),

    ]

8 访问http://127.0.0.1:8000/lecture/query/

可以得到与第9节类似的页面