JSONField dictionary/object lookup using an "integer" key

[Shaheed Haque]

The documentation on performing queries inside JSONField values ​https://docs.djangoproject.com/en/2.0/ref/contrib/postgres/fields/#key-index-and-path-lookups says:

If the key is an integer, it will be interpreted as an index lookup in an array:

>>> Dog.objects.filter(data__owner__other_pets__0__name='Fishy')

Note the specific mention of array. While this might be true, it is not the whole truth as applied to dict/object. For example, given a dict/object whose keys are strings (as always in JSON) but which look like integers:

  "employee": {
    "415": {
      "email": "Sherlock.Holmes@acme.co.uk",
      "mobile": "0700 1234567",

how is one supposed to select the "415" bit? It turns out that the same syntax as for the array case applies:

Foo.objects.filter(snapshot__employee__415__mobile='0700 1234567')

This was not at all obvious to me at least, especially as if the "415" is looked up as the terminal level in the query, the syntax becomes very different:

Foo.objects.filter(snapshot__employee__has_key='415')

Since I wasted quite a bit of time on this, I thought it might be useful to strengthen the documentation in this area to clarify how to lookup:

• In arrays and dict/objects
  • if the key is the final term in the query
  • if the key is not the final term in the query