兩個表格篩選器

Question

我嘗試篩選具有特定類別的Book類的作者，但無法獲得確切的類別。

models.py

class Book(models.Model): 
    category = models.CharField() 
    foreignkey = models.ForeignKey(Author, related_name="auth") 
class Author(models.Model): 
    author_id = models.IntegerField(primary_key=True) 

views.py

book = models.Book.objects.filter(category = 'Space') 
author = models.Author.objects.filter(author_id__in = book) 

Answer 1

class Book(models.Model): 
    category = models.CharField() 
    author = models.ForeignKey(Author, related_name='books') 

class Author(models.Model): 
    name = models.CharField() 


books = Book.objects.values('author_id',flat=True).filter(category='Space') 
authors = Author.objects.filter(pk__in=books) 

Answer 2

class Book(models.Model): 
    category = models.CharField() 
    author = models.ForeignKey(Author, related_name='books') 

class Author(models.Model): 
    # pks are added automatically 

在views.py

books = models.Book.objects.filter(category='Space') 
authors = models.Author.objects.filter(pk__in=[b.author_id for b in books])