django orm中的过滤场M2M
我的模型:
class Tag(models.Model):
tag_name = models.CharField(
'Tag Name',
max_length=255,
null=True
)
class Book(models.Model):
name = models.CharField(
'Name',
max_length=255,
null=True
)
tag = models.ManyToManyField(
'Tag',
related_name='tags',
blank=True
)
我不会过滤书的模型。在DB中,我有几行:
标签
| id |名称|
| ----- | ------- |
| 1 | tag_1 |
| 2 | tag_2 |
| 3 | tag_3 |
书
| id |名称|标签|
| ----- | ------- | ------- |
| 1 | book_1 | tag_1 |
| 2 | book_2 | tag_2 |
| 3 | book_3 | tag_3 |
| 4 | book_4 | tag_1,tag_2,tag_3 |
如果我使用tag = tag_1,tag_2的新模型书,我该如何过滤书籍模型,并且我想在书本模型中找到所有带有标签的模型,包括tag_1或tag_2。 我想要这样的QuerySet(对于TAG = TAG_1,TAG_2):
[(id=1, name=book_1), (id=2, name=book_2), (id=4, name=book_4)]
My models:
class Tag(models.Model):
tag_name = models.CharField(
'Tag Name',
max_length=255,
null=True
)
class Book(models.Model):
name = models.CharField(
'Name',
max_length=255,
null=True
)
tag = models.ManyToManyField(
'Tag',
related_name='tags',
blank=True
)
I wont filtering Book's model. In db i have several rows:
Tag
| id | name |
|-----|------|
| 1 |tag_1 |
| 2 |tag_2 |
| 3 |tag_3 |
Book
| id | name | tags |
|-----|-------|------|
| 1 |book_1 |tag_1|
| 2 |book_2 |tag_2|
| 3 |book_3 |tag_3|
| 4 |book_4 |tag_1, tag_2, tag_3|
How can i filtering book models, if i take new model Book with tag=tag_1, tag_2 and i want find in Book models all model with tag include tag_1 or tag_2.
I want get queryset like this(for tag=tag_1, tag_2):
[(id=1, name=book_1), (id=2, name=book_2), (id=4, name=book_4)]
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如果我理解您的问题,您有一个具有tag_1和tag_2标签的book_5,并且您想根据book_5标签过滤书籍。
您可以使用 value_list
您可以将标签QuerySet变成ID列表,然后基于此筛选您的书籍。
所以是:
If I understand your question you have a book_5 which has tags of tag_1 and tag_2 and you want to filter books based on book_5 tags.
you can use value_list
you can turn your tags queryset into a list of IDs and then filter you books based on that.
so it would be: