287 lines
6.8 KiB
Markdown
287 lines
6.8 KiB
Markdown
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# Django CRUD 应用程序
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> 原文：<https://www.askpython.com/django/django-crud-application>
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在本文中，我们将了解 Django CRUD 应用程序由什么组成，然后创建我们自己的 CRUD 应用程序。
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## 什么是 Django CRUD 应用程序？
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CRUD 应用程序是一个处理**CRUD——创建、检索、更新和删除**操作的网站。CRUD 应用程序的一个典型例子是**学生数据**应用程序。在此类应用中，您可以:
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* **添加/创建**新的学生数据
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* **检索**当前学生的数据
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* **更新/编辑**已经是学生的数据
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* **删除**一个学生数据
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我们现在将了解这些操作中的每一项
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CRUD
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* **创建:**在数据库中创建或添加新条目
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* **检索:**从数据库中获取条目
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* **更新:**更新数据库中的特定条目
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* **删除:**从数据库中删除特定条目
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## 在 Django 中创建我们自己的 CRUD 应用程序
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现在让我们创建一个简单的**学生数据** CRUD 应用程序。
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### 1.创建模型表
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为了存储数据，我们需要创建一个 [Django 模型](https://www.askpython.com/django/django-models)。因此，将以下模型添加到您的文件中。
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```py
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class StudentModel(models.Model):
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id = models.IntegerField(primary_key = True)
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student_name = models.CharField(max_length=80)
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rollnumber = models.CharField(max_length=10)
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student_class = models.IntegerField()
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student_age = models.IntegerField()
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def __str__(self):
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return f"{self.student_name} : {self.rollnumber}"
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```
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### 2.创建模型表单
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我们还需要一个[模型表单](https://www.askpython.com/django/django-model-forms)来向用户显示模型字段。
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```py
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class StudentForm(forms.ModelForm):
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class Meta:
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model = StudentModel
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fields = ('id','student_name','rollnumber','student_class','student_age')
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```
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### 3.编写创建视图的代码
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在 Views.py 中创建视图**“create View”**并添加以下代码:
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```py
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from .models import StudentModel
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from .forms import StudentForm
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from django.shortcuts import render,redirect
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def CreateView(request):
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if request.method == 'POST':
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form = StudentForm(request.POST)
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if form.is_valid():
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form.save()
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return redirect('/data')
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else:
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form =StudentForm()
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context = {
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'form':form
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}
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return render(request,'create.html',context)
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```
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模板**“create . html**”将看起来像:
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```py
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<form method = "post">
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{% csrf_token %}
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{{form.as_p}}
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<input type = "submit" value = "submit">
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</form>
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```
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视图的 URL 路径将是:
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```py
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path('data/create', CreateView),
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```
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### 4.对检索视图进行编码
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现在在检索操作中，有两种可能的方法
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* 显示所有数据列表 **( [Django 列表视图](https://www.askpython.com/django/django-listview) )**
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* 仅显示特定数据 **( [Django 详细视图](https://www.askpython.com/django/django-detailview) )**
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因此，将以下两个视图添加到 views.py 文件中
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```py
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from django.shortcuts import render,redirect
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from .models import StudentModel
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from .forms import StudentForm
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def Retrieve_ListView(request):
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dataset = StudentModel.objects.all()
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return render(request,'listview.html',{'dataset':dataset})
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def Retrieve_DetailView(request,_id):
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try:
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data =StudentModel.objects.get(id =_id)
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except StudentModel.DoesNotExist:
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raise Http404('Data does not exist')
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return render(request,'detailview.html',{'data':data})
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```
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相应的 **ListView** 模板将是:
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```py
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{% for data in dataset %}
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{{data}}
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<hr>
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{% endfor %}
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```
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相应的**详细视图**模板将是:
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```py
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<h3>Name:{{data.student_name}}</h3><br>
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<h3>Roll Number:{{data.rollnumber}}</h3><br>
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<h3>Class:{{data.student_class}}</h3><br>
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<h3>Age:{{data.student_age}}</h3><br>
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<hr/>
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```
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视图的 URL 路径将是:
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```py
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path('data/', Retrieve_ListView),
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path('data/<int:_id>',Retrieve_DetailView),
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```
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### 5.更新视图编码
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现在将下面的更新视图添加到 views.py 文件中
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```py
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from django.shortcuts import render,redirect,get_object_or_404
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from .models import StudentModel
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from .forms import StudentForm
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def UpdateView(request,_id):
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try:
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old_data = get_object_or_404(StudentModel,id =_id)
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except Exception:
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raise Http404('Does Not Exist')
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if request.method =='POST':
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form =StudentForm(request.POST, instance =old_data)
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if form.is_valid():
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form.save()
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return redirect(f'/data/{_id}')
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else:
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form = StudentForm(instance = old_data)
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context ={
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'form':form
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}
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return render(request,'update.html',context)
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```
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相应的**update.html**模板将看起来像这样:
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```py
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<form method="post">
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{% csrf_token %}
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{{form.as_p}}
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<input type="submit" value = "Update">
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</form>
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```
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视图的 URL 路径将是:
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```py
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path('data/<int:_id>/update', UpdateView),
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```
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### 6.对删除视图进行编码
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现在将**删除视图**添加到 views.py 文件中
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```py
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def DeleteView(request,_id):
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try:
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data = get_object_or_404(StudentModel,id =_id)
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except Exception:
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raise Http404('Does Not Exist')
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if request.method == 'POST':
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data.delete()
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return redirect('/data')
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else:
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return render(request, 'delete.html')
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```
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相应的**delete.html**会是什么样子:
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```py
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<form method="post">
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{% csrf_token %}
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Click YES to confirm
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<input type = "submit" value="YES">
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<a href='/data'>Cancel</a>
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</form>
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```
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视图的 URL 路径将是:
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```py
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path('data/<int:_id>/delete', DeleteView),
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```
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## **实现学生应用**
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编码部分就这样了！！现在启动服务器，让我们转到“ **/data/create** ”端点
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Create
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点击提交，您将到达显示学生列表的 **"/data"** 页面。
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Retrieve List View
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现在尝试“ **/data/1** ”端点
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Retrieve Detail View
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好了伙计们。！让我们更新第一个条目。转到“**/数据/1/更新**”
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Update
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进行一些更改并点击“更新”,您将被重定向到特定学生的详细视图页面。
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最后，让我们尝试删除第一个学生。进入**/数据/1/删除**
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Delete
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点击 **YES** 并检查，特定的学生数据将从数据库中删除。
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## **结论**
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就这样，编码员们！！这都是关于 **CRUD** 应用程序的。一定要看看 **[Django REST API](https://www.askpython.com/django/django-rest-api)** 教程，这是一个 CRUD 应用程序的 REST API 版本。
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下一篇文章再见！！在那之前继续编码！！
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