### 11.3 图书管理系统#### 11.3.1 出版社的管理

展示：- 设计URL- ```pythonurlpatterns = [url(r'^publisher_list',views.publisher_list)]```- 写函数- ```pythonfrom django.shortcuts import renderfrom app01 import models#展示出版社def publisher_list(request):#从数据库中查询到出版社的信息all_publishers = models.Publisher.object.all()#返回到一个包含出版社信息的页面return render(request,'publisher_list.html',{'all-publishers':all_publishers})```- 写模板- ```html<table boder = '1'><thead><th>序号</th><th>ID</th><th>名称</th></thead>{% for publisher in all_publishers %}<tr><td>{{forloop.counter}}</td>   #自带的功能，生成对应序号<td>{{publisher.pk}}</td>    #pk就是primary key主键<td>{{publisher.name}}</td></tr></table>```新增：```python
obj = models.Publisher.object.create(name=publisher_name)
```删除```python
obj_list = models.Publisher.objects.filter(pk=pk)
obj_list.delete()obj = models.Publisher.objecct.get(pk=pk)
obj.delete()
```编辑```python
#修改数据
#首先要获取数据
obj = models.Publisher.objects.filter(name)   # 不考虑重复、空值等情况
obj.name = publisher_name
obj.save
```#### 11.3.2 书籍管理
```python
class Book(models.Model):title = models.CharField(max_length=32)pub = models.ForeignKey('Publisher',on_delete=models.CASCADE) #级连删除，一个表删除，另一个对应的也会删除

on_delete的参数：models.CASCADE models.SET_DEFAULT models.SET_null
```查询：```python
all_book = models.Book.objects.all()for book in all_book:print(book.title)print(book.pub)   #所关联的出版社对象print(book.pub.pk)   #查id  多了一次查询print(book.pub_id)   #支架在book表中查出的IDprint(book.pub.name)
```新增：```python
models.Book.object.create(title=book_name,pub=出版社的对象)
models.Book.object.create(title=book_name,pub_id=pub_id)
```删除：```python
ps = request.get('id')
models.Book.object.filter(pk=pk).delete()
```编辑：```html
{% if book_obj.pub == publisher%}<option selected value="{{publisher.pk}}">{{publisher.name}}</option>
{% else %}<option value="{{publisher.pk}}">{{publisher.name}}</option>
{% endif %}
``````python
#修改数据
book_obj.title = book_name
book.obj.pub = models.Publisher.objects.get(pk=pub_id)
book_obj.save()
```#### 11.3.3 作者管理1.创建作者表```python
class Author(models.Model):name = models.CharField(max_length=32)book = models.ManyToManFieldy('Book')
```2.展示```python
#展示作者
def author_list(request):#查询到所有对象all_author = models.Author.object.all()return render(request,'author_list.html',{'all_author':all_author})``````html
#写模板
{%  for author in all_author%}<tr><td>{{forloop.counter}}</td><td>{{author.pk}}</td><td>{{author.name}}</td><td>{% for book in author.book.all%}{%  if forloop.last%}《{{book.title}}》{% else %}《{{book.title}}》{%endif%}{%endfor%}</td></tr>
{%endfor%}
```3.增加```python
author_obj = models.Author.objects.create(name=author_name) #只插入到book表中的内容
author_obj = models.set(book)   #设置作者和书籍的多对多的关系
```4.修改```python
book = request.POST.getlist('book')    #获取多个值得时候要用getlist#修改对象的数据
author_obj.name = name
author_obj.save()
#多对多的关系
author_obj.book.set(books)   #每次重新设置
```##### 11.3.3.1 django设置多对多关系的三种方法1.django帮助我们生成第三张表```python
class Author(models.Model):name = models.CharField(max_length=32)books = models.ManyToManyField('Book')  # 不在Author表中生产字段，生产第三张表
```2.自己创建第三场表```python
class AuthorBook(models.Model):author = models.ForeignKey(Author, on_delete=models.CASCADE)book = models.ForeignKey(Book, on_delete=models.CASCADE)date = models.DateField()
```3.自建的表和ManyToMany联合使用```python
class Author(models.Model):name = models.CharField(max_length=32)books = models.ManyToManyField('Book',through='AuthorBook')  # 不在Author表中生产字段，生产第三张表class AuthorBook(models.Model):author = models.ForeignKey(Author, on_delete=models.CASCADE)book = models.ForeignKey(Book, on_delete=models.CASCADE)date = models.DateField()
```