【问题标题】：steps for deleting data in a table using django & mysql db使用 django 和 mysql db 删除表中数据的步骤
【发布时间】：2013-03-01 05:13:32
【问题描述】：

我使用 django 和 MySQL 作为数据库来执行添加、编辑和删除详细信息。我使用下面的代码执行了添加和编辑，但删除不起作用。

views.py：

import logging
import smtplib
from django.db import connection
from django.shortcuts import render
from django.http import HttpResponse
from polls.models import Poll
from django.template import Context, loader
from django.shortcuts import get_object_or_404, render_to_response
from myapp.models import Book
from django.shortcuts import render_to_response,redirect
from django.shortcuts import get_object_or_404, render
from django.http import HttpResponseRedirect
from django.core.context_processors import csrf
from django.template import RequestContext

log = logging.getLogger(__name__)

def index(request):

    books = Book.objects.all()
    context={'books':books}
    return render(request,'index.html', context)

def addbook(request):
    if request.POST:
        book_name =request.POST['book_name']
        author_name =request.POST['author_name']
    publisher_name =request.POST['publisher_name']
    book = Book(book_name=book_name, author_name=author_name, publisher_name=publisher_name)
        book.save()
        return render_to_response('book_detail.html', {'books': book},context_instance=RequestContext(request))
    else:
        return render_to_response('addbook.html',context_instance=RequestContext(request))

def book_detail(request):
    return render(request, 'book_detail.html') 

def editbook(request,book_id):
    if request.POST:
        book_name =request.POST['book_name']
        author_name =request.POST['author_name']
    publisher_name =request.POST['publisher_name']
    books=Book.objects.filter(book_id=book_id).update(book_name=book_name, author_name=author_name, publisher_name=publisher_name)
        return redirect('/index/')
    else:
        books = Book.objects.get(pk=book_id)
    return render_to_response('editbook.html',{'books':books},context_instance=RequestContext(request))

def deletebook(request,book_id):
    if request.POST:
        book_name =request.POST['book_name']
        author_name =request.POST['author_name']
    publisher_name =request.POST['publisher_name']
    books=Book.objects.filter(book_id=book_id).delete(book_name=book_name, author_name=author_name, publisher_name=publisher_name)
        return redirect('/index/')
    else:
        books = Book.objects.get(pk=book_id)
    return render_to_response('deletebook.html',{'books':books},context_instance=RequestContext(request))

urls.py:

from django.conf.urls import patterns, include, url
from DemoApp.views import index,addbook,editbook, book_detail
from django.contrib import admin

admin.autodiscover()

urlpatterns = patterns('',
    url('^$', index),
    url('^index/$', index),
    url('^addbook/$', addbook),
    url('^book_detail/$', book_detail, 'book_summary'),
    url('^editbook/(?P<book_id>\d+)/$',editbook) ,
    url('^deletebook/(?P<book_id>\d+)/$',deletebook) ,

    #url(r'^admin/', include(admin.site.urls)),

)

HTML 模板：

<html>
    <head>
        <title>{{ page_title }}</title>
    </head>
    <body>   
        <div align="center">
            <table border="0" cellpadding='5' cellspacing='5'>
                <tr>
                    <form action="/deletebook/{{ books.book_id}}/" method="POST"> {% csrf_token %}
                        <input type="text" name="book_name" value="{{books.book_name}}"></input><br>
                        <input type="text" name="author_name" value="{{books.author_name}}"></input><br>
                        <input type="text" name="publisher_name" value="{{books.publisher_name}}"></input><br>
                        <input type="submit" value="delete">
                    </form>
                    <p> Output: {{ output }} </p>
                    <p>{{ book_name }}</p>
                </tr>  
            </table>
        </div>
    </body>
</html>

我没有使用任何形式。我无法对特定行执行 delete 操作。它给出了一条错误消息。请检查这个 sn-p 并用正确的回复我。

我的要求是我想从表中删除选定的行。我正在使用 MySQL。

【问题讨论】：

我需要通过python代码在view.py中执行这个..请帮助我
view.py 中用于删除数据库中一行而不是整个表的代码

标签： mysql django-templates django-views

【解决方案1】：

我对 django 了解不多，但是清空表的 SQL 命令是：

TRUNCATE table table_name;

它会将自动增量重新设置为 1，如果您不想更改该使用：

Delete * from table_name;

如果你想删除特定的行，那么

Delete from table_name where conditions1, condition2

【讨论】：

【解决方案2】：

首先尝试打印您从查询中获得的值，以确定是否有任何内容符合您的delete 条件：

books = Book.objects.filter(book_id=book_id, book_name=book_name, author_name=author_name, publisher_name=publisher_name)
print '\n'.join([str(b) for b in books])

如果您已经给出了book_id，为什么还要查询book_name、author_name 和publisher_name？我想您想删除与给定 id 匹配的书籍（将来会非常感谢更多的散文）。查询将是：

Book.objects.filter(book_id=book_id).delete()

另外，请确保book_id 是Book 的现有属性。 By default，Django 使用名为 id 的主键，book_id 将是您手动更改的内容。

【讨论】：

【解决方案3】：

从 Django 中的表中删除一行的简单解决方案

urls.py

url(r'^Books_Admin/$', views.Books_Admin,name="Books_Admin"),

url(r'^BookInfoDelete/(?P<Isbn>\w+)/$', views.BookInfoDelete,name="BookInfoDelete"),

/* Isbn 是表的主键。 */

views.py

from django.shortcuts import render,redirect
from .models import BookInfo

def Books_Admin(request):
        books = BookInfo.objects.all()
        return render(request,"Books_Admin.html",{'books':books})

def BookInfoDelete(request,Isbn):
    if request.method == 'POST':
        BookInfo.objects.filter(Isbn=Isbn).delete()
        return redirect(' After deletion which page you want to see, put that url here in sigle qoutes ')

// 这里 BookInfo 是表名。 // 这里 Books_Admin 定义用于查看表 BookInfo

models.py

from django.db import models

class BookInfo(models.Model):
    Isbn = models.CharField(max_length=20, primary_key = True)
    Book_Name = models.CharField(max_length=200)
    Author = models.CharField(max_length=100)
    Publisher = models.CharField(max_length=150)
    Availability = models.CharField(max_length=15)

// 表BookInfo的创建

HTML

<table class="table table-hover tab">
            <thead>
              <tr>
                <th>ISBN</th>
                <th>Book Name</th>
                <th>Author</th>
                <th>Publisher</th>
              </tr>
            </thead>
            {% for Books in books %}
              <tr>
                <td>{{ Books.Isbn }}</td>
                <td>{{ Books.Book_Name }}</td>
                <td>{{ Books.Author }}</td>
                <td>{{ Books.Publisher }}</td>
                <td>
                  <form action="/BookInfoDelete/{{ Books.Isbn }}/" method="post">
                    {% csrf_token %}
                    <button type="submit" class="btn btn-danger"><span class="glyphicon glyphicon-trash"></span></button>
                </form>
                </td>
              </tr>
            {% endfor %}
          </table>

【讨论】：

【解决方案4】：

{% for i in obj %}
 
 <a href="{% url 'product_delete' %}?id={{ i.id }}"><button type="submit" class="btn btn-primary">Delete</button></a>

{% endfor %}

product_delete 是我在views.py中写的函数

urls.py 文件：

urlpatterns = [
path('page', views.page, name='page')
path('product_delete', views.product_delete, name='product_delete')
]

views.py 文件：

def page(request):
    return render(request, "page.html")

def product_delete(request):
    if request.GET.get('id'):
        i=request.GET['id']
        with connection.cursor() as cursor:
                        cursor.execute('delete from abc where id=%s',[i])
    return redirect ("page")

abc 是表名。

页面将是我们删除产品或条目后要返回的位置。

记得在views.py中导入一个库为：

from django.db import connection

如果不导入连接，光标将不起作用。

它会从您的 HTML 页面以及数据库中删除特定产品。

【讨论】：