CODEWITHSUNDEEP
pythondjango
aircraft
aircraft

Reputation: 26896

How to three-level query in Django?

I have three tables, names A, B, C:

class A(models.Model):
    name = models.CharField(max_length=12)

class B(models.Model):
    name = models.CharField(max_length=12)
    a = models.ForeignKey(to=A)

class C(models.Model):
    name = models.CharField(max_length=12)
    email = models.EmailField()
    b = models.ForeignKey(to=B)

I want get the bellow data:

[
    {"name":"a1",
     "data":[{
        "name":"b1",
        "data":[
           {"name":"c1",
           "data":{"c1_name":"c1_name", "c1_id":"c1_id"}
           },
           {"name":"c2",
           "data":{"c2_name":"c2_name", "c2_id":"c2_id"}
           }
        ] 
     },
    {
        "name":"b2",
        "data":[
           {"name":"c1",
           "data":{"c1_name":"c1_name", "c1_id":"c1_id"}
           },
           {"name":"c2",
           "data":{"c2_name":"c2_name", "c2_id":"c2_id"}
           }
          ] 
          }
        ]
    }
]

You see, there is three-level data, if there is only table A and B, I can multi-table connection query:

B.objects.filter(a='search_id')

But now there is three tables, and you see the table C's email is not contain in the query data. How to realize this requirement in my scenario?

Upvotes: 0

Views: 222

Answers (1)

masterfloda
masterfloda

Reputation: 3038

As @Brian H. is pointing out in the comments, you can chain foreign keys with __.

In your case you could get the data with

C.objects.filter(b__a='search_id').values('id', 'name', 'b__name', 'b__a__name')

You can then loop through the data and build the list in the format you require.

Upvotes: 1

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