Elasticsearch Understanding and Implementing Elasticsearch Get Mapping

By Opster Team

Updated: Jul 20, 2023

| 2 min read

Introduction

Elasticsearch Get Mapping is a crucial feature that allows users to retrieve mapping definitions for an index or type. Mapping is the process of defining how a document and its fields are stored and indexed. In this article, we will delve into the details of Elasticsearch Get Mapping, its usage, and how to implement it effectively.

The Importance of Get Mapping

Get Mapping plays a vital role in Elasticsearch operations. It provides the structure of the index, including the field names and their data types. This information is essential when creating or updating documents in an index, as it ensures data consistency and optimizes search operations.

Using the Get Mapping API

The Get Mapping API is used to retrieve the mapping definitions of an index or type. The basic syntax is as follows:

GET /<index>/_mapping

In this command, `<index>` is the name of the index for which you want to retrieve the mapping. If you want to retrieve the mapping for all indices, you can use `_all` or `*` instead of specifying an index name.

Here is an example of using the Get Mapping API:

GET /my_index/_mapping

This command will return the mapping for the `my_index` index.

 Understanding the Response

The response from the Get Mapping API includes the index name, followed by the mapping definitions. Each field in the mapping is represented by a JSON object, which includes the field name and its properties. The properties can include the field type, analyzer, and other settings.

Here is an example of a response:

json
{
  "my_index" : {
    "mappings" : {
      "properties" : {
        "name" : {
          "type" : "text"
        },
        "age" : {
          "type" : "integer"
        }
      }
    }
  }
}

In this response, the `my_index` index has two fields: `name` and `age`. The `name` field is of type `text`, and the `age` field is of type `integer`.

Updating the Mapping

While you can’t change the mapping of an existing field, you can add new fields to the mapping. To do this, you can use the Put Mapping API. The basic syntax is as follows:

PUT /<index>/_mapping
{
  "properties": {
    "<field>": {
      "type": "<type>"
    }
  }
}

In this command, `<index>` is the name of the index, `<field>` is the name of the new field, and `<type>` is the data type of the new field.

Here is an example of using the Put Mapping API:

json
PUT /my_index/_mapping
{
  "properties": {
    "email": {
      "type": "keyword"
    }
  }
}

This command will add a new field named `email` of type `keyword` to the `my_index` index.

Conclusion 

In conclusion, Elasticsearch Get Mapping is a powerful tool that provides insights into the structure of your indices. By understanding and effectively using this feature, you can ensure data consistency and optimize your search operations.