CODEWITHSUNDEEP
elasticsearch
user10400458
user10400458

Reputation:

Multiple mappings for one index in Elasticsearch 6

I have an index that contains documents of different types (not talking about _type here) and each document has a field document_type that states their type. Is it possible to define mappings for each type of document within this index?

Upvotes: 2

Views: 7538

Answers (3)

cinhtau
cinhtau

Reputation: 1042

Is it possible to define mappings for each type of document within this index?

No, if you think of using the same field name with different types. For instance, field name id of type string and integer won't work.

Having different document_type basically indicates different domains. What you could do is to group information under each respective domain or type. For instance, an employee and project, both have an id and name, but different types in this example. Some call that nesting.

An example index mapping:

PUT example
{
  "settings": {
    "number_of_shards": 1,
    "number_of_replicas": 0
  }, 
  "mappings": {
    "doc": {
      "properties": {
        "employee": {
          "properties": {
            "id": {
              "type": "integer"
            },
            "name": {
              "type": "text",
              "fields": {
                "keyword": {
                  "type": "keyword",
                  "ignore_above": 64
                }
              }
            }
          }
        },
        "project": {
          "properties": {
            "id": {
              "type": "keyword"
            },
            "name": {
              "type": "keyword",
              "ignore_above": 32
            }
          }
        }
      }
    }
  }
}

If you write the information, with different types.

PUT example/doc/1
{
  "employee": {
    "id": 4711,
    "name": "John Doe"
  },
  "project": {
    "id": "Project X",
    "name": "Firebrand"
  }
}

Others would argue to store employee and project in separate indices. This approach depends on your scenario and is also desirable. You allow both domains to evolve separately from each other.

Having a separate employee and project index gives you an advantage regarding maintenance. For querying some would argue, that you can group than with an alias. In the above example, it doesn't make sense since the field types are different. A search for the name over an analysed text field is different than over a keyword. Querying makes sense if you have the same field type.

Upvotes: 2

Opster Elasticsearch Expert
Opster Elasticsearch Expert

Reputation: 1855

Having a single field name with more than one mapping type in the same index is not possible. Two options I can think of: 1. Separate the different doc types to separate indices. 2. Use different fields names for different doc types, so that each name can have different mapping. You can also use nesting, like: type_a.my_field and type_b.my_field, both in the same index.

Upvotes: 0

Albert
Albert

Reputation: 221

No, if you want to use a single index, you would need to define a single mapping that combines the fields of each document type.

A better way might be to define separate indices on the same cluster for each document type. You can then create a single index alias that aliases to both of those indices if you want to be able to query across document types. Be sure that all fields that exist in both documents have the same data type in both mappings.

Upvotes: 0

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