In the previous chapter, we learned many things about querying Elasticsearch. We saw how to choose fields that will be returned and learned how querying works in Elasticsearch. In addition to that, we now know the basic queries that are available and how to filter our data. What's more, we saw how to highlight the matches in our documents and how to validate our queries. In the end, we saw the compound queries of Elasticsearch and learned how to sort our data. By the end of this chapter, you will have learned the following topics:
Indexing tree-like structured data
Indexing data that is not flat
Modifying your index structure when possible
Indexing data with relationships by using nested documents
Indexing data with relationships between them by using the parent-child functionality