使用另一个查询集过滤查询集

Question

Hi i'm not very good at English but i'll try to explain myself the best i could. I'm using python and Django to create a web project. I have this 4 models (this is the best translation i can do of the tables and fields):

class Humans (models.Model): 
    name = models.CharField(max_length=15)
    surname = models.CharField(max_length=15)
    doc_num = models.CharField(max_length=11)
    ...

class Records (models.Model): 
    closing_state = models.CharField(max_length=2)
    ...
    humans = models.ManyToManyField(Humans, through='Reco_Huma')

class Reco_Huma (models.Model): 
    id_record = models.ForeignKey(Records)
    id_human = models.ForeignKey(Humans)
    categorys = models.CharField(max_length=2)
    reserv_identity = models.CharField(max_length=2)
    repre_entity = models.CharField(max_length=2)


class Observations (models.Model): 
    id_record = models.ForeignKey(Records)
    text = models.CharField(max_length=80)
    category = models.CharField(max_length=2, choices=CAT)

Now given a doc_num from Humans, a text from Observations i want to get a QuerySet Of all the Records.

To clarify i first do this:

q1 = Reco_Huma.objects.filter(id_human.doc_num=x)
q2 = Observations.objects.filter(text=y)

both query-sets give me a list of id_record and then i want to connive that lists and filter the Records table with that id_record's

I hope you can understand me

Thanks in advance

Answer 1

To rephrase your query, you want all the Records associated with a certain Human and which have a certain Observation. So it should be:

result = Records.objects.filter(observations__text=y, humans__doc_num=x)

As a general rule, if you want to end up with a certain type of object, it helps to start from there in your query.