Python - Django - ORM 实例（二）
在 app01/models.py 中添加 Book 类对象表
from django.db import models
# Create your models here.
# 出版社
class Publisher(models.Model):
id = models.AutoField(primary_key=True) # 自增的 ID 主键
# 创建一个 varchar(64) 的唯一的不为空的字段
name = models.CharField(max_length=64, null=False, unique=True)
# 书籍
class Book(models.Model):
id = models.AutoField(primary_key=True) # 自增的 ID 主键
# 创建一个 varchar(64) 的唯一的不为空的字段
title = models.CharField(max_length=64, null=False, unique=True)
# 和出版社关联的外键字段
publisher = models.ForeignKey(to="Publisher")
然后执行命令更新到数据库中
manage.py@mysite0 > makemigrations manage.py@mysite0 > migrate
在 Book 表中添加 3 条数据
展示书籍列表：
创建 book_list.html：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>书籍列表</title>
</head>
<body>
<table border="1">
<thead>
<tr>
<th>id</th>
<th>书名</th>
<th>出版社</th>
</tr>
</thead>
<tbody>
{% for book in book_list %}
<tr>
<td>{{ book.id }}</td>
<td>{{ book.title }}</td>
<td>{{ book.publisher.name }}</td>
</tr>
{% endfor %}
</tbody>
</table>
</body>
</html>
这里的 book.publisher 获取到的是 Publisher 对象，因为 publisher 关联了 Publisher 对象
在 app01/views.py 中添加 book_list 函数
from django.shortcuts import render, redirect, HttpResponse
from app01 import models
# 展示出版社列表
def publisher_list(request):
# 去数据库查出所有的出版社，填充到 html 中，返回给用户
ret = models.Publisher.objects.all().order_by("id") # order_by("id") 通过 id 进行排序
return render(request, "publisher_list.html", {"publisher_list": ret})
# 添加新的出版社
def add_publisher(request):
# 如果是 POST 请求，就获取用户填写的数据
if request.method == "POST":
new_publisher = request.POST.get("publisher_name")
# 获得数据后去数据库中新增一条数据
models.Publisher.objects.create(name=new_publisher)
# 添加成功后进行跳转
return redirect("/publisher_list/")
# 用户来到该界面返回的 html 页面
return render(request, "add_publisher.html")
# 删除出版社
def del_publisher(request):
# 从 GET 请求的参数中拿到要删除的 id 值
del_id = request.GET.get('id')
# 如果取到 id 值，就去数据库中删除该 id 的数据
if del_id:
# 根据 id 查找数据，并删除
del_obj = models.Publisher.objects.get(id=del_id).delete()
# 删除后返回页面
return redirect("/publisher_list/")
else:
return HttpResponse("要删除的数据不存在！")
# 编辑出版社
def edit_publisher(request):
# 获取 POST 发来的数据，并更新到数据库中
if request.method == "POST":
# 获取 POST 传送来的 id 值和出版社
edit_id = request.POST.get('id')
new_name = request.POST.get('publisher_name')
# 根据 id 取得出版社
publisher = models.Publisher.objects.get(id=edit_id)
publisher.name = new_name
publisher.save() # 把修改的结果提交到数据库
return redirect("/publisher_list/") # 跳转到列表页面
# 从 GET 请求中取得 id 值
publisher_id = request.GET.get('id')
if publisher_id:
# 获取当前编辑的出版社对象
publisher_obj = models.Publisher.objects.get(id=publisher_id)
return render(request, "edit_publisher.html", {"publisher": publisher_obj})
else:
return HttpResponse("编辑的出版社不存在！")
# 展示书籍列表
def book_list(request):
# 去数据库中查询所有书籍
all_book = models.Book.objects.all()
# 渲染数据
return render(request, "book_list.html", {"book_list": all_book})
在 mysite0/urls.py 中添加对应关系
from django.conf.urls import url
from django.contrib import admin
from app01 import views
urlpatterns = [
url(r'^publisher_list/', views.publisher_list),
url(r'^add_publisher/', views.add_publisher),
url(r'^del_publisher/', views.del_publisher),
url(r'^edit_publisher/', views.edit_publisher),
url(r'^book_list/', views.book_list),
]
运行结果：
添加书籍：
修改 book_list.html：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>书籍列表</title>
</head>
<body>
<table border="1">
<thead>
<tr>
<th>id</th>
<th>书名</th>
<th>出版社</th>
</tr>
</thead>
<tbody>
{% for book in book_list %}
<tr>
<td>{{ book.id }}</td>
<td>{{ book.title }}</td>
<td>{{ book.publisher.name }}</td>
</tr>
{% endfor %}
</tbody>
</table>
<a href="/add_book/">添加书籍</a>
</body>
</html>
创建 add_book.html：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>添加书籍</title>
</head>
<body>
<h1>添加书籍</h1>
<form action="/add_book/" method="post">
<p>
书名:<input type="text" name="book_title">
</p>
<p>
出版社:
<select name="publisher" >
{% for publisher in publisher_list %}
<option value="{{ publisher.id }}">{{ publisher.name }}</option>
{% endfor %}
</select>
</p>
<p>
<input type="submit" value="提交">
</p>
</form>
</body>
</html>
在 app01/views.py 中添加 add_book 函数
from django.shortcuts import render, redirect, HttpResponse
from app01 import models
# 展示出版社列表
def publisher_list(request):
# 去数据库查出所有的出版社，填充到 html 中，返回给用户
ret = models.Publisher.objects.all().order_by("id") # order_by("id") 通过 id 进行排序
return render(request, "publisher_list.html", {"publisher_list": ret})
# 添加新的出版社
def add_publisher(request):
# 如果是 POST 请求，就获取用户填写的数据
if request.method == "POST":
new_publisher = request.POST.get("publisher_name")
# 获得数据后去数据库中新增一条数据
models.Publisher.objects.create(name=new_publisher)
# 添加成功后进行跳转
return redirect("/publisher_list/")
# 用户来到该界面返回的 html 页面
return render(request, "add_publisher.html")
# 删除出版社
def del_publisher(request):
# 从 GET 请求的参数中拿到要删除的 id 值
del_id = request.GET.get('id')
# 如果取到 id 值，就去数据库中删除该 id 的数据
if del_id:
# 根据 id 查找数据，并删除
del_obj = models.Publisher.objects.get(id=del_id).delete()
# 删除后返回页面
return redirect("/publisher_list/")
else:
return HttpResponse("要删除的数据不存在！")
# 编辑出版社
def edit_publisher(request):
# 获取 POST 发来的数据，并更新到数据库中
if request.method == "POST":
# 获取 POST 传送来的 id 值和出版社
edit_id = request.POST.get('id')
new_name = request.POST.get('publisher_name')
# 根据 id 取得出版社
publisher = models.Publisher.objects.get(id=edit_id)
publisher.name = new_name
publisher.save() # 把修改的结果提交到数据库
return redirect("/publisher_list/") # 跳转到列表页面
# 从 GET 请求中取得 id 值
publisher_id = request.GET.get('id')
if publisher_id:
# 获取当前编辑的出版社对象
publisher_obj = models.Publisher.objects.get(id=publisher_id)
return render(request, "edit_publisher.html", {"publisher": publisher_obj})
else:
return HttpResponse("编辑的出版社不存在！")
# 展示书籍列表
def book_list(request):
# 去数据库中查询所有书籍
all_book = models.Book.objects.all()
print(all_book)
# 渲染数据
return render(request, "book_list.html", {"book_list": all_book})
# 添加书籍
def add_book(request):
if request.method == "POST":
new_title = request.POST.get("book_title")
new_publisher_id = request.POST.get("publisher")
# 去数据库中创建数据
models.Book.objects.create(title=new_title, publisher_id=new_publisher_id)
return redirect("/book_list/")
# 去数据库取得出版社数据展示在页面上以供用户选择
publishers = models.Publisher.objects.all()
return render(request, "add_book.html", {"publisher_list": publishers})
在 mysite0/urls.py 中添加对应关系
from django.conf.urls import url
from django.contrib import admin
from app01 import views
urlpatterns = [
url(r'^admin/', admin.site.urls),
url(r'^publisher_list/', views.publisher_list),
url(r'^add_publisher/', views.add_publisher),
url(r'^del_publisher/', views.del_publisher),
url(r'^edit_publisher/', views.edit_publisher),
url(r'^book_list/', views.book_list),
url(r'^add_book/', views.add_book),
]
运行结果：
点击“添加书籍”
点击“提交”
删除书籍：
修改 book_list.html：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>书籍列表</title>
</head>
<body>
<table border="1">
<thead>
<tr>
<th>id</th>
<th>书名</th>
<th>出版社</th>
<th>操作</th>
</tr>
</thead>
<tbody>
{% for book in book_list %}
<tr>
<td>{{ book.id }}</td>
<td>{{ book.title }}</td>
<td>{{ book.publisher.name }}</td>
<td>
<a href="/del_book/?id={{ book.id }}">删除</a>
</td>
</tr>
{% endfor %}
</tbody>
</table>
<a href="/add_book/">添加书籍</a>
</body>
</html>
在 app01/views.py 中添加 del_book 函数
from django.shortcuts import render, redirect, HttpResponse
from app01 import models
# 展示出版社列表
def publisher_list(request):
# 去数据库查出所有的出版社，填充到 html 中，返回给用户
ret = models.Publisher.objects.all().order_by("id") # order_by("id") 通过 id 进行排序
return render(request, "publisher_list.html", {"publisher_list": ret})
# 添加新的出版社
def add_publisher(request):
# 如果是 POST 请求，就获取用户填写的数据
if request.method == "POST":
new_publisher = request.POST.get("publisher_name")
# 获得数据后去数据库中新增一条数据
models.Publisher.objects.create(name=new_publisher)
# 添加成功后进行跳转
return redirect("/publisher_list/")
# 用户来到该界面返回的 html 页面
return render(request, "add_publisher.html")
# 删除出版社
def del_publisher(request):
# 从 GET 请求的参数中拿到要删除的 id 值
del_id = request.GET.get('id')
# 如果取到 id 值，就去数据库中删除该 id 的数据
if del_id:
# 根据 id 查找数据，并删除
del_obj = models.Publisher.objects.get(id=del_id).delete()
# 删除后返回页面
return redirect("/publisher_list/")
else:
return HttpResponse("要删除的数据不存在！")
# 编辑出版社
def edit_publisher(request):
# 获取 POST 发来的数据，并更新到数据库中
if request.method == "POST":
# 获取 POST 传送来的 id 值和出版社
edit_id = request.POST.get('id')
new_name = request.POST.get('publisher_name')
# 根据 id 取得出版社
publisher = models.Publisher.objects.get(id=edit_id)
publisher.name = new_name
publisher.save() # 把修改的结果提交到数据库
return redirect("/publisher_list/") # 跳转到列表页面
# 从 GET 请求中取得 id 值
publisher_id = request.GET.get('id')
if publisher_id:
# 获取当前编辑的出版社对象
publisher_obj = models.Publisher.objects.get(id=publisher_id)
return render(request, "edit_publisher.html", {"publisher": publisher_obj})
else:
return HttpResponse("编辑的出版社不存在！")
# 展示书籍列表
def book_list(request):
# 去数据库中查询所有书籍
all_book = models.Book.objects.all()
print(all_book)
# 渲染数据
return render(request, "book_list.html", {"book_list": all_book})
# 添加书籍
def add_book(request):
if request.method == "POST":
new_title = request.POST.get("book_title")
new_publisher_id = request.POST.get("publisher")
# 去数据库中创建数据
models.Book.objects.create(title=new_title, publisher_id=new_publisher_id)
return redirect("/book_list/")
# 去数据库取得出版社数据展示在页面上以供用户选择
publishers = models.Publisher.objects.all()
return render(request, "add_book.html", {"publisher_list": publishers})
# 删除书籍
def del_book(request):
# 从 URL 中获取要删除的书籍的 id
del_id = request.GET.get("id")
# 去数据库中删除指定 id 的书籍
models.Book.objects.get(id=del_id).delete()
# 跳转到书籍列表页面
return redirect("/book_list/")
在 mysite0/urls.py 中添加对应关系
from django.conf.urls import url
from django.contrib import admin
from app01 import views
urlpatterns = [
url(r'^admin/', admin.site.urls),
url(r'^publisher_list/', views.publisher_list),
url(r'^add_publisher/', views.add_publisher),
url(r'^del_publisher/', views.del_publisher),
url(r'^edit_publisher/', views.edit_publisher),
url(r'^book_list/', views.book_list),
url(r'^add_book/', views.add_book),
url(r'^del_book/', views.del_book),
]
运行结果：
删除“PHP”
页面闪了一下，PHP 就被删除了
编辑书籍：
修改 book_list.html：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>书籍列表</title>
</head>
<body>
<table border="1">
<thead>
<tr>
<th>id</th>
<th>书名</th>
<th>出版社</th>
<th>操作</th>
</tr>
</thead>
<tbody>
{% for book in book_list %}
<tr>
<td>{{ book.id }}</td>
<td>{{ book.title }}</td>
<td>{{ book.publisher.name }}</td>
<td>
<a href="/del_book/?id={{ book.id }}">删除</a>
<a href="/edit_book/?id={{ book.id }}">编辑</a>
</td>
</tr>
{% endfor %}
</tbody>
</table>
<a href="/add_book/">添加书籍</a>
</body>
</html>
创建 edit_book.html：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>编辑书籍</title>
</head>
<body>
<h1>编辑书籍</h1>
<form action="/edit_book/" method="post">
<input type="text" style="display: none" name="id" value="{{ book_obj.id }}">
<p>
书名:
<input type="text" name="book_title" value="{{ book_obj.title }}">
</p>
<p>
出版社:
<select name="publisher">
{% for publisher in publisher_list %}
{# 通过 if 条件判断来选择默认出版社 #}
{% if book_obj.publisher_id == publisher.id %}
{# 默认选择当前书籍关联的出版社 #}
<option selected value="{{ publisher.id }}">{{ publisher.name }}</option>
{% else %}
{# 其他的出版社不选中 #}
<option value="{{ publisher.id }}">{{ publisher.name }}</option>
{% endif %}
{% endfor %}
</select>
</p>
<p>
<input type="submit" value="提交">
</p>
</form>
</body>
</html>
在 app01/views.py 中添加 edit_book 函数
from django.shortcuts import render, redirect, HttpResponse
from app01 import models
# 展示出版社列表
def publisher_list(request):
# 去数据库查出所有的出版社，填充到 html 中，返回给用户
ret = models.Publisher.objects.all().order_by("id") # order_by("id") 通过 id 进行排序
return render(request, "publisher_list.html", {"publisher_list": ret})
# 添加新的出版社
def add_publisher(request):
# 如果是 POST 请求，就获取用户填写的数据
if request.method == "POST":
new_publisher = request.POST.get("publisher_name")
# 获得数据后去数据库中新增一条数据
models.Publisher.objects.create(name=new_publisher)
# 添加成功后进行跳转
return redirect("/publisher_list/")
# 用户来到该界面返回的 html 页面
return render(request, "add_publisher.html")
# 删除出版社
def del_publisher(request):
# 从 GET 请求的参数中拿到要删除的 id 值
del_id = request.GET.get('id')
# 如果取到 id 值，就去数据库中删除该 id 的数据
if del_id:
# 根据 id 查找数据，并删除
del_obj = models.Publisher.objects.get(id=del_id).delete()
# 删除后返回页面
return redirect("/publisher_list/")
else:
return HttpResponse("要删除的数据不存在！")
# 编辑出版社
def edit_publisher(request):
# 获取 POST 发来的数据，并更新到数据库中
if request.method == "POST":
# 获取 POST 传送来的 id 值和出版社
edit_id = request.POST.get('id')
new_name = request.POST.get('publisher_name')
# 根据 id 取得出版社
publisher = models.Publisher.objects.get(id=edit_id)
publisher.name = new_name
publisher.save() # 把修改的结果提交到数据库
return redirect("/publisher_list/") # 跳转到列表页面
# 从 GET 请求中取得 id 值
publisher_id = request.GET.get('id')
if publisher_id:
# 获取当前编辑的出版社对象
publisher_obj = models.Publisher.objects.get(id=publisher_id)
return render(request, "edit_publisher.html", {"publisher": publisher_obj})
else:
return HttpResponse("编辑的出版社不存在！")
# 展示书籍列表
def book_list(request):
# 去数据库中查询所有书籍
all_book = models.Book.objects.all()
print(all_book)
# 渲染数据
return render(request, "book_list.html", {"book_list": all_book})
# 添加书籍
def add_book(request):
if request.method == "POST":
new_title = request.POST.get("book_title")
new_publisher_id = request.POST.get("publisher")
# 去数据库中创建数据
models.Book.objects.create(title=new_title, publisher_id=new_publisher_id)
return redirect("/book_list/")
# 去数据库取得出版社数据展示在页面上以供用户选择
publishers = models.Publisher.objects.all()
return render(request, "add_book.html", {"publisher_list": publishers})
# 删除书籍
def del_book(request):
# 从 URL 中获取要删除的书籍的 id
del_id = request.GET.get("id")
# 去数据库中删除指定 id 的书籍
models.Book.objects.get(id=del_id).delete()
# 跳转到书籍列表页面
return redirect("/book_list/")
# 编辑书籍
def edit_book(request):
# 从 POST 数据中提取书籍 id 和书籍名及出版社
if request.method == "POST":
edit_id = request.POST.get("id")
new_title = request.POST.get("book_title")
new_publisher_id = request.POST.get("publisher")
# 更新数据
edit_book_obj = models.Book.objects.get(id=edit_id)
edit_book_obj.title = new_title
edit_book_obj.publisher_id = new_publisher_id
# 将更新的数据提交到数据库中
edit_book_obj.save()
# 跳转到书籍列表页面
return redirect("/book_list/")
# 取得编辑书籍的 id
book_id = request.GET.get("id")
# 根据 id 去数据库中取得书籍数据
book_obj = models.Book.objects.get(id=book_id)
publisher_obj = models.Publisher.objects.all()
return render(request, "edit_book.html", {"publisher_list": publisher_obj, "book_obj": book_obj})
在 mysite0/urls.py 中添加对应关系
from django.conf.urls import url
from django.contrib import admin
from app01 import views
urlpatterns = [
url(r'^admin/', admin.site.urls),
url(r'^publisher_list/', views.publisher_list),
url(r'^add_publisher/', views.add_publisher),
url(r'^del_publisher/', views.del_publisher),
url(r'^edit_publisher/', views.edit_publisher),
url(r'^book_list/', views.book_list),
url(r'^add_book/', views.add_book),
url(r'^del_book/', views.del_book),
url(r'edit_book/', views.edit_book),
]
运行结果：
编辑“《C++》”
改成“《C》”，“乙出版社”
