# One-to-many relationships with recursive relationships
**URL:** https://discuss.elastic.co/t/one-to-many-relationships-with-recursive-relationships/5719
**Category:** Elasticsearch
**Created:** [October 28, 2011, 9:34pm UTC](https://discuss.elastic.co/t/one-to-many-relationships-with-recursive-relationships/5719 "2011-10-28T21:34:23Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Runar\_Myklebust](https://discuss.elastic.co/u/Runar_Myklebust)
#### Post date: [October 28, 2011, 9:34pm UTC](https://discuss.elastic.co/t/one-to-many-relationships-with-recursive-relationships/5719/1 "2011-10-28T21:34:23Z")
Hi.
Im doing a pilot for introducing ES as the search-engine in our
product.
The main entity to index is "content", which is pretty straight
forward to index.
The problems arises when having to deal with content-placement
(categories, menu-items), security and other meta-data.
Lets take categories as an example. A content is resident in one
category only. Categories are arranged as trees.
A typical query could be like: "Fetch all content in a category X and
include all sub-categories"
Lets say the category-tree could be e.g 10 levels deep, so we
potentionally will get a large number of categories to consider.
Things to consider:
1. Response-time
2. Update data, e.g move a category
Approach 1: Include category-id in content index, resolve all
categories before query and apply them as Filter.
Pros: Easy to maintain
Cons: Potentially very large filters, lets say like 1000 category-keys
-\> how bad is that?
Approach 2: Store category path in content, apply query with main
category and number of levels to include
Pros: Simple query
Cons: Hard to maintain e.g when moving a category
Approach 3: I then though about normalizing the data, storing content
with category-id, and the store category with path. But I not quite
shure how to map and query this? My initial thought was to use a child-
parent approach, with an "inner query" finding matching categories and
joining them with all matching content.category-ids, but Im not even
sure this is possible.
Any thoughts on how to approach this? Or any other approaches?
---
### Author:  [@Sky\_Stebnicki1](https://discuss.elastic.co/u/Sky_Stebnicki1)
#### Post date: [January 24, 2013, 2:30pm UTC](https://discuss.elastic.co/t/one-to-many-relationships-with-recursive-relationships/5719/2 "2013-01-24T14:30:23Z")
Hi Runar,
I know this is sort of old, but I didn't see a reply. Were you able to
determine what would be the best solution for this problem? We have a
similar issue where we are trying to query all sub-folders of the current
folder (in a file system index).
Thanks,
Sky
On Friday, October 28, 2011 2:34:23 PM UTC-7, Runar Myklebust wrote:
> Hi.
>
> Im doing a pilot for introducing ES as the search-engine in our
> product.
>
> The main entity to index is "content", which is pretty straight
> forward to index.
> The problems arises when having to deal with content-placement
> (categories, menu-items), security and other meta-data.
>
> Lets take categories as an example. A content is resident in one
> category only. Categories are arranged as trees.
>
> A typical query could be like: "Fetch all content in a category X and
> include all sub-categories"
>
> Lets say the category-tree could be e.g 10 levels deep, so we
> potentionally will get a large number of categories to consider.
>
> Things to consider:
>
> 1. Response-time
> 2. Update data, e.g move a category
>
> Approach 1: Include category-id in content index, resolve all
> categories before query and apply them as Filter.
> Pros: Easy to maintain
> Cons: Potentially very large filters, lets say like 1000 category-keys
> -\> how bad is that?
>
> Approach 2: Store category path in content, apply query with main
> category and number of levels to include
> Pros: Simple query
> Cons: Hard to maintain e.g when moving a category
>
> Approach 3: I then though about normalizing the data, storing content
> with category-id, and the store category with path. But I not quite
> shure how to map and query this? My initial thought was to use a child-
> parent approach, with an "inner query" finding matching categories and
> joining them with all matching content.category-ids, but Im not even
> sure this is possible.
>
> Any thoughts on how to approach this? Or any other approaches?
--
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 2:54am UTC](https://discuss.elastic.co/t/one-to-many-relationships-with-recursive-relationships/5719/3 "2017-07-06T02:54:44Z")