CODEWITHSUNDEEP
elasticsearch
Asciiom
Asciiom

Reputation: 9975

How to specify or target a field from a specific document type in queries or filters in Elasticsearch?

Given:

  1. Documents of two different types, let's say 'product' and 'category', are indexed to the same Elasticsearch index.
  2. Both document types have a field 'tags'.

Problem:

I want to build a query that returns results of both types, but the documents of type 'product' are allowed to have tags 'X' and 'Y', and the documents of type 'category' are only allowed to have tag 'Z'. How can I achieve this? It appears I can't use product.tags and category.tags since then ES will look for documents' product/category field, which is not what I intend.

Note:

While for the example above there might be some kind of workaround, I'm looking for a general way to target or specify fields of a specific document type when writing queries. I basically want to 'namespace' the field names used in my query so only documents of the type I want to work with are considered.

Upvotes: 3

Views: 295

Answers (1)

Andrzej Martyna
Andrzej Martyna

Reputation: 475

I think field aliasing would be the best answer for you, but it's not possible. Instead you can use "copy_to" but I it probably affects index size:

DELETE /test
PUT /test
{
      "mappings": {
          "product" : {
              "properties": { 
                "tags": { "type": "string", "copy_to": "ptags" },
                "ptags": { "type": "string" }
            }
            },
          "category" : {
              "properties": { 
                "tags": { "type": "string", "copy_to": "ctags" },
                "ctags": { "type": "string" }
            }
        }
    }
}

PUT /test/product/1
{ "tags":"X" }
PUT /test/product/2
{ "tags":"Y" }
PUT /test/category/1
{ "tags":"Z" }

And you can query one of fields or many of them:

GET /test/product,category/_search
{
    "query": {
        "term": {
           "ptags": {
              "value": "x"
           }
        }
    }
}

GET /test/product,category/_search
{
    "query": {
        "multi_match": {
        "query":      "x",
        "fields":     [ "ctags", "ptags" ]
        }
    }
}

Upvotes: 2

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