Django与ForeignKey值完全匹配

Question

class Sentence(Model):
    name = CharField()

class Tokens(Model):
   token = CharField()
   sentence = ForeignKey(Sentence, related_name='tokens')

1. 我想实现两个案例:句子完全由三个令牌组成['I', 'like', 'apples'].所以列表sentence.tokens.all() 是完全正确的['I', 'like', 'apples'].

2. 与上面相同,但包含令牌(句子的一部分).

Sentence.objects.annotate(n=Count('tokens',distinct=True)).filter(n=3).filter(tokens__name='I').filter(tokens__name='like').filter(tokens__name='apples')不起作用,因为它也匹配I I I.

有没有办法过滤ForeignKey中的确切值集？

Answer 1

啊,我现在更好地理解这个问题.只需利用您和Jay的代码元素,以下可能是一种方法.可能不是很优雅.但似乎工作.

def get_sentences(my_tokens):
    counts = dict()
    for t in my_tokens:
        counts[t] = my_tokens.count(t)
    results = Sentence.objects
    for k, v in counts.iteritems():
        results = results.filter(tokens__token=k).annotate(n=Count('tokens',distinct=True)).filter(n__gte=v)
    return results

>>> from django.db.models import Count
>>> from my.models import Sentence, Tokens

>>> s1 = Sentence.objects.create(name="S1")
>>> t10 = Tokens.objects.create(token="I", sentence=s1)
>>> t20 = Tokens.objects.create(token="like", sentence=s1)
>>> t30 = Tokens.objects.create(token="apples", sentence=s1)

>>> s2 = Sentence.objects.create(name="S2")
>>> t11 = Tokens.objects.create(token="I", sentence=s2)
>>> t21 = Tokens.objects.create(token="like", sentence=s2)
>>> t31 = Tokens.objects.create(token="oranges", sentence=s2)

>>> s3 = Sentence.objects.create(name="S3")
>>> t31 = Tokens.objects.create(token="I", sentence=s3)
>>> t32 = Tokens.objects.create(token="I", sentence=s3)
>>> t33 = Tokens.objects.create(token="I", sentence=s3)

>>> my_toks = ("I", "like", "apples")
>>> sentences = get_sentences(my_toks)
>>> sentences[0].name
u'S1'

>>> my_toks = ("I", "I", "I")
>>> sentences = get_sentences(my_toks)
>>> sentences[0].name
u'S3'

为了确切参考,我的模型看起来像这样:

class Sentence(Model):
    name = models.CharField(max_length=16)

class Tokens(Model):
    token = models.CharField(max_length=16)
    sentence = models.ForeignKey(Sentence, related_name='tokens')