Django：ORM基本操作-CRUD，管理器对象objects，-----＞查询3（单条更新，批量更新）

>>> b1 = Book.objects.get(id=1)
>>> b1
<Book: 书名：python_出版社：清华大学出版社_价格：20.00_市场价：25.00>
>>> b1.price = 22
>>> b1.save()

Microsoft Windows [版本 10.0.19042.928]
(c) Microsoft Corporation。保留所有权利。C:\Users\520>cd..C:\Users>cd..C:\>program files\mysql\mysql server 8.0\bin
'program' 不是内部或外部命令，也不是可运行的程序
或批处理文件。C:\>cd program files\mysql\mysql server 8.0\binC:\Program Files\MySQL\MySQL Server 8.0\bin>mysql -uroot -p
Enter password: ****
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 49
Server version: 8.0.25 MySQL Community Server - GPLCopyright (c) 2000, 2021, Oracle and/or its affiliates.Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.mysql> use mysite;           # mysite是project名称
Database changed
mysql> show tables;
+----------------------------+
| Tables_in_mysite           |
+----------------------------+
| auth_group                 |
| auth_group_permissions     |
| auth_permission            |
| auth_user                  |
| auth_user_groups           |
| auth_user_user_permissions |
| author                     |
| book                       |
| django_admin_log           |
| django_content_type        |
| django_migrations          |
| django_session             |
+----------------------------+
12 rows in set (0.05 sec)mysql> desc book-> ^C
mysql> desc book;
+--------------+--------------+------+-----+---------+----------------+
| Field        | Type         | Null | Key | Default | Extra          |
+--------------+--------------+------+-----+---------+----------------+
| id           | bigint       | NO   | PRI | NULL    | auto_increment |
| title        | varchar(50)  | NO   | UNI | NULL    |                |
| price        | decimal(7,2) | NO   |     | NULL    |                |
| market_price | decimal(7,2) | NO   |     | NULL    |                |
| pub          | varchar(100) | NO   |     | NULL    |                |
+--------------+--------------+------+-----+---------+----------------+
5 rows in set (0.03 sec)mysql> select * from book;
+----+--------+-------+--------------+----------------+
| id | title  | price | market_price | pub            |
+----+--------+-------+--------------+----------------+
|  1 | python | 22.00 |        25.00 | 清华大学出版社 |
|  2 | django | 70.00 |        75.00 | 清华大学出版社 |
|  3 | jquery | 90.00 |        85.00 | 机械工业出版社 |
|  4 | linux  | 80.00 |        65.00 | 机械工业出版社 |
|  5 | html5  | 90.00 |       105.00 | 清华大学出版社 |
+----+--------+-------+--------------+----------------+
5 rows in set (0.01 sec)mysql>

>>> books = Book.objects.filter(pub="清华大学出版社")
>>> books.update(price=1)
3
>>> bs = Book.objects.filter(pub="清华大学出版社")
>>> for book in bs:
...     print(book.price)
...
1.00
1.00
1.00
>>>

mysql> select * from book;
+----+--------+-------+--------------+----------------+
| id | title  | price | market_price | pub            |
+----+--------+-------+--------------+----------------+
|  1 | python |  1.00 |        25.00 | 清华大学出版社 |
|  2 | django |  1.00 |        75.00 | 清华大学出版社 |
|  3 | jquery | 90.00 |        85.00 | 机械工业出版社 |
|  4 | linux  | 80.00 |        65.00 | 机械工业出版社 |
|  5 | html5  |  1.00 |       105.00 | 清华大学出版社 |
+----+--------+-------+--------------+----------------+
5 rows in set (0.00 sec)mysql>

总路由

from django.contrib import admin
from django.urls import path, includeurlpatterns = [path('admin/', admin.site.urls),path("bookstore/", include("myapp.urls"))
]

子路由

from django.urls import path
from . import viewsurlpatterns = [path("all_book", views.all_book),path("update_book/<int:book_id>", views.update_book)
]

myapp.views.py

from django.shortcuts import render
from django.http import HttpResponse, HttpResponseRedirect
from .models import Book# Create your views here.
def all_book(request):all_book = Book.objects.all()return render(request, "myapp/abook.html", locals())def update_book(request, book_id):# 查try:book = Book.objects.get(id=book_id)except Exception as e:print("update book error is {}".format(e))return HttpResponse("book {} does not exist".format(book_id))if request.method == "GET":return render(request, "myapp/update_book.html", locals())elif request.method == "POST":price = request.POST['price']market_price = request.POST['market_price']# 改book.price = pricebook.market_price = market_price# 存book.save()return HttpResponseRedirect("/bookstore/all_book")  # 注意：相对地址

abook.html

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>查看所有书籍</title>
</head>
<body>
<table border="1"><tr><th>id</th><th>title</th><th>pub</th><th>price</th><th>market_price</th><th>op</th></tr><tr>{% for book in all_book %}<tr><td>{{ book.id }}</td><td>{{ book.title }}</td><td>{{ book.pub }}</td><td>{{ book.price }}</td><td>{{ book.market_price }}</td><td><a href="/bookstore/update_book/{{ book.id }}">更新</a><a href="">删除</a></td></tr>{% endfor %}</tr>
</table></body>
</html>

update_book.html

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>更新书籍</title>
</head>
<body><form action="/bookstore/update_book/{{ book_id }}" method="post">{% csrf_token %}<!--这里提交到的URL要注意，使用相对地址，最前面的斜杠不要丢--><p>title<input type="text" value="{{ book.title }}" disabled="disabled"></p>  <!--没有给name，点击提交时不会提交这个值。disabled属性，值不可修改 --><p>pub<input type="text" value="{{ book.pub }}" disabled="disabled"></p><p>price<input type="text" name="price" value="{{ book.price }}"></p><p>market_price<input type="text" name="market_price" value="{{ book.market_price }}"></p><p><input type="submit" value="更新啦"></p>
</form></body>
</html>

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