Query all of a given category (with sub-categories)

Users Dgraph
,
1

I Want to Do

I have two types of Nodes, Categories and Products - and Categories can have related subcategories (which are themselves Categories).

I’m trying to query root Categories (categories without any parent category), each with a list of communities representing all the communities related to any subcategory of that root category.

Using @recurse gives me a nested result, (Category → Subcategory → [Communities]) - but I’m looking to return a flattened list (Category → [Communities])

Any help is appreciated!!

2

Recurse won’t work for that case. Try to use normalize

{
  q(func: type(Category)) @filter(NOT has(<~Subcategory>)) {
    Subcategory @normalize {
      Communities: Communities
    }
  }
}

What are(I mean the type) Communities? a string? objects? How many sub cats it can have?

3

Communities are nodes as well.

Normalize as above will return a category object with a normalized subcategory field. I’m looking to return a community field with a list of any community related to any subcategory - if that makes sense.

I’d like to traverse the graph until all subcategories (and subcategories of subcategories) are traversed.

4

How many sub cats it may have? Do you mind sharing the desired result? I think I know how to. But a mock of the desired result would be great.

5

How many sub cats it may have?

Unlimited

Desired result:

{
  "data": {
    "query": [
      {
        "uid": "0x9df7",
        "Category.name": "Example Category",
         "products": [
           {uid: "0xxdf7", product_name: "Example Product"},
           {uid: "0xfdf7", product_name: "Example Product #2"},
           ......
         ]
      }
    ]
  }
}
6

The products are under Communities?

7

Sorry, I meant to write Category - not Communities.

Categories have many products, and products can have many categories.

8

Thinking…

Can you share the recurse query you have tried?

The way I have thought would work for a single root category. So you would do a query for each category.

9

Actually, I think I was able to figure it out with your help :slight_smile:

{
  query(func: type(Category)) @filter(NOT has(Category.categories)) @recurse {
    uid
    name: Category.name
    products: Category.products
    product_name: Product.name
  }
}
10

The only thing is I had to add the parent categories to all child products to get this to work :confused: Do you know of a way where this isn’t needed?

11

Nice, I was about to recommend this

{
  query(func: type(Category)) @filter(NOT has(Category.categories)) @recurse {
    uid
    name: Category.name
    products: Category.products @normalize
    product_name: Product.name
  }
}

To check if it work.

12

Actually nevermind - that did work!

13

Not sure if I got.

This predi param (NOT has(Category.categories)) should not be reversed? - nvm too

14

Thanks for the help :pray:

1 Like
15

@MichelDiz Sorry, I was manually adding the Products to the parent Category - so it turns out that this:

{
  query(func: type(Category)) @filter(NOT has(Category.parent_categories)) @recurse {
    uid
    name: Category.name
    products: Category.products
    product_name: Product.name
  }
}

returns:

{
"data": {
    "query": [
      {
        "uid": "0x9e23",
        "name": "Category #1 (no subcategories)",
        "products": [
          {
            "uid": "0x9e24",
            "product_name": "Product #1"
          }
        ]
      },
      {
        "uid": "0x9e28",
        "name": "Category #2 (with subcategories))"
      }
    ]
  }
}

The problem is that Product #2 is related the a subcategory of Category #2, which are being filtered out by @filter(NOT has(Category.parent_categories))

So, still stuck :rofl:

16

@MichelDiz I think what I need is

_foreach
1 Like
17

Weird. So why this appears in the response? it should be filtered out. The category itself should be excluded if it has Category.parent_categories predicate.

The params at the query root are applied only in the root objects. The nested ones follows the rules in the query body.

18

Category #2 has no parents - so it appears.

Category #3 is a subcategory of Category #2, so it doesn’t appear.

Product #2 is listed under Category #3, so it’s not returned either.