So far, when we searched our data we used the REST API and a simple query or the GET request. Similarly, when we changed the index, we also used the REST API and sent the JSON-structured data to Elasticsearch, regardless of the type of operation we wanted to perform—whether it was a mapping change or document indexation. A similar situation happens when we want to send more than a simple query to Elasticsearch—we structure it using JSON objects and send it to Elasticsearch. This is called the query DSL. In a broader view, Elasticsearch supports two kinds of queries: basic ones and compound ones. Basic queries such as the term query are used for querying the actual data. We will cover these in the Basic queries section of this chapter. The second type of query is the compound query, such as the bool query, which can combine multiple queries. We will cover these in the Compound queries section of this chapter.

However, this is not the whole picture. In addition to these...