Cloudant selector query array field

Question

I've a cloudant documents that contains this specific structure a json array of category that contains array of subcategories , and i'm trying to write a cloudant query that returns documents with given category_id (for example 128) my problem that it's an array . for example :

"category": {
    "sub_category": [
      {
        "name": {
          "en": "Fast food"
        },
        "category_id": "127"
      },
      {
        "name": {
          "en": "Resturans"
        },
        "category_id": "128"
      }
    ],
}

so far i've tried to write this index :

{
   "index": {},
   "type": "text"
}

to index everything and a selector :

{"category.sub_category":{"$elemMatch" : {"category_id": {"$gt": 128" }}}

but it doesn't work. any help?

Answer 1

It looks like you are storing category_id as a string, but then trying to perform a numeric comparison. If you change your category_ids to integers:

"category_id": 127
...
"category_id": 128

then this selector should work:

"category.sub_category": {
    "$elemMatch" : {
        "category_id": {"$gt": 126 }
    }
}

Note: I changed the value in the query to 126 because your sample values were 127 and 128 and would not pass the original query (> 128).

Alternatively, if you wanted to keep category_id as a string and you wanted to find all documents where the category_id equals "128" then you could use the following selector:

"_id": { "$gt": null },
"category.sub_category": {
    "$elemMatch" : {
        "category_id": {"$eq": "128" }
    }
}