CRUD Operations on Documents in Elasticsearch

Elasticsearch is a distributed, open-source search and analytics engine. It provides powerful capabilities to handle and manage large volumes of data efficiently. One fundamental aspect of working with Elasticsearch is performing CRUD (Create, Read, Update, Delete) operations on documents. In this article, we will explore these operations and understand how to apply them effectively in Elasticsearch.

Create

To create a document in Elasticsearch, you need to index it within a specific index. An index is a logical container that holds documents of similar or related types. The following is an example of how to create a document using the Elasticsearch API:

PUT /index_name/_doc/document_id
{
  "field1": "value1",
  "field2": "value2",
  ...
}

In the above example, index_name represents the name of the index where the document will be stored, document_id should be a unique identifier for the document, and the JSON body includes the fields and values of the document.

Read

Reading documents in Elasticsearch involves searching and retrieving data based on certain criteria. Here are a few ways you can read documents:

• Get Document by ID: To retrieve a document by its unique identifier, use the following API call:

  GET /index_name/_doc/document_id

• Query Documents: Elasticsearch offers a powerful query DSL (Domain Specific Language) to perform complex searches on documents. You can search for documents based on specific field values, perform full-text search, filter results, and more. Here's an example of a simple query:

  POST /index_name/_search
  {
    "query": {
      "match": {
        "field1": "value1"
      }
    }
  }

  This query will return all documents in index_name where the field1 has the value of "value1".

Update

Updating documents in Elasticsearch allows you to modify existing fields or add new ones. To update a document, you need to perform a partial update operation or reindex the entire document. Here's an example of updating a document using the partial update API:

POST /index_name/_update/document_id
{
  "doc": {
    "field1": "new_value",
    "new_field": "value"
  }
}

In the above example, Elasticsearch will update the value of field1 to "new_value" and add a new field called new_field with the value of "value".

Delete

Deleting documents in Elasticsearch can be done on a single document or multiple documents matching a specific criteria. Here's the syntax for deleting a document:

DELETE /index_name/_doc/document_id

To delete multiple documents, you can utilize the delete_by_query API:

POST /index_name/_delete_by_query
{
  "query": {
    "match": {
      "field1": "value1"
    }
  }
}

In the above example, Elasticsearch will delete all documents in index_name where field1 has the value of "value1".

Conclusion

CRUD operations are the backbone of data management in Elasticsearch. By understanding how to create, read, update, and delete documents, you can effectively utilize the power of Elasticsearch in organizing and retrieving your data. Experiment with these operations to gain proficiency and take advantage of Elasticsearch's capabilities.