django-models，views.py和模板到外鍵分配

Question

models.py

class Author(models.Model):
    author_id=models.AutoField(primary_key=True)
    first_name = models.CharField(max_length=30)
    last_name = models.CharField(max_length=40)
    email = models.EmailField()
    age=models.IntegerField()

    class Meta:
    db_table=u'Author Info'

    def __unicode__(self):
        return u"%d %s %s %s %d" % (self.pk, self.first_name, self.last_name, self.email,self.age)

    def books(self):
        return Book.objects.filter(author=self)

class Book(models.Model):
    book_id=models.AutoField(primary_key=True,unique=True)
    book_name=models.CharField(max_length=30)
    publisher_name=models.CharField(max_length=40)
    author=models.ForeignKey(Author)

    class Meta:
        db_table = u'Book Name'

    def __unicode__(self):
        return u'%d %s %s' % (self.pk, self.book_name, self.publisher_name)

views.py

def addbook(request):
    if request.POST:
        first_name = request.POST.get('first_name')
        last_name = request.POST.get('last_name')
        email = request.POST.get('email')
        age = request.POST.get('age')
    author = Author(first_name = first_name,last_name = last_name,email=email,age=age)
        author=author.save()
        book_name = request.POST.get('book_name')
        publisher_name = request.POST.get('publisher_name')
    #Book.author_id=author
        #author_id = author_id()
        book=Book.objects.create(book_name=book_name,publisher_name=publisher_name,author_id)
    book.save()
    return redirect('/index/')
    else:
        return render_to_response('addbook.html',context_instance=RequestContext(request))

的index.html /模板

table border="0" cellpadding='8' cellspacing='10'>
    <tr>
        <td align="right" colspan="8"><a href="/addbook/">Add Book</a></td>
    </tr>

    <tr>
        <th>Book Id</>
    <th>Book name</th>
    <th>Publication name</th>
    <th>Author Id</th>
    <th>First Name</th>
    <th>Last Name</th>
    <th>E Mail</th>
    <th>Age</th>
    </tr>
    {% for book in books %}
    <tr>
       <td>{{ book.book_id }}</td>
       <td>{{ book.book_name }}</td>
       <td>{{ book.publisher_name }}</td>
       <td>{{ book.author_id }}</td>

       {% for author in authors %}  
         <td>{{author.first_name}} </td><td>{{author.last_name}}</td>
         <td>{{author.email}}</td>
         <td>{{author.age}}</td>
           {% endfor %}
             <td><a href="/editbook/{{ book.book_id}}">Edit</a></td>
             <td><a href="/deletebook/{{ book.book_id}}">Delete</a></td>
        {% endfor %}

這里如何在Book類中為“author”或author_id字段分配外鍵值，請給出賦值程序。我無法設置值給forreign鍵字段...如何分配或者是否有其他可用功能請解釋我

Answer 1

Integrity錯誤是由於null值傳遞給Book表的author_id列。 檢查此行book=Book.objects.create(book_name=book_name,publisher_name=publisher_name,author_id)

如果你想在book表中插入相同的作者id，你可以使用

Django的信號

或者您必須通過查詢一些獨特的參數（比如電子郵件ID值）從Author表中獲取最新的作者ID，並將此ID傳遞給Books表

Answer 2

問題是這樣的：

author = Author(first_name = first_name,last_name = last_name,email=email,age=age)
author=author.save()

save()實際上並沒有返回任何東西，即使我相信它應該。 將其更改為：

author = Author(first_name = first_name,last_name = last_name,email=email,age=age)
author.save()
book.author = author
book.save()

現在你有了你的作者，你可以分配給book.author 。

而且，雖然我在這里，你應該了解反向關系 。 不需要以下方法：

def books(self):
    return Book.objects.filter(author=self)

因為你可以這樣做：

author.book_set.all()