Question

你好我正在研究django。我有两本模特书籍和作者，但它们之间没有外键关系。

型号：

class Books(models.Model):
  bookid = models.IntegerField(primary_key=True)
  bookname = models.CharField(max_length=50)
  authorid = models.CharField(max_length=50)

  class Meta:
    managed = False
    db_table = 'books'

class Authors(models.Model):
  authorid = models.IntegerField(primary_key=True)
  authorname = models.CharField(max_length=50)


  class Meta:
    managed = False
    db_table = 'authors'

现在，我想根据作者姓名获取作者和相关书籍。

class Author_Books(generics.GenericAPIView):
def get(self, request, *args, **kwargs):
    try:
        authorname = 'Author Name'

        # filtering authors

        authors = Authors.objects.filter(authorname__icontains=authorname)

        # get author related books 

            How to acheive it without using raw sql query.


        return HttpResponse(authors)

    except Exception as err:
        return HttpResponse(err)

Answer 1

您可以使用以下查询。

for author in authors:
    books = Books.objects.filter(authorid = author.authorid )

注意：最好链接作者和books表。

Answer 2

试试这个，

مرحبا

注意：您必须在两个表之间建立外键关系，这是最佳做法
示例：

class Author_Books(generics.GenericAPIView): def get(self, request, *args, **kwargs): try: authorname = 'Author Name' # Changes # auther_qryset = Authors.objects.filter(authorname__icontains=authorname) authorid_list = auther_qryset.values_list('authorid', flat=True) # returns a 'list' contains `authorid` book_queryset = Books.objects.filter(authorid__in=authorid_list) # do something with "book_queryset" return HttpResponse(authors) except Exception as err: return HttpResponse(err)

Answer 3

如果要使用一个SQL（连接两个表）从数据库中获取数据，则必须在模型中使用django ForeignKey，否则django后端将查询两次。喜欢这个

author = Authors.objects.get(pk=1)
books = Books.objects.filter(authorid=author.id)

如果使用foreignkey

books = Books.objects.filter(foreignkey__authorname=authorname)

Django查询两个没有外键的表

3 个答案: