Elasticsearch does not only support simple unrelated documents, it also lets you define a hierarchy based on our parent and children. The
has_child query allows querying for parent documents of children matching other queries.
You need an up-and-running Elasticsearch installation as we described in the Downloading and installing Elasticsearch recipe in Chapter 2, Downloading and Setup.
curl via the command line, you need to install
curl for your operating system.
To correctly execute the following commands, you need an index populated with the
chapter_07/populate_relations.sh script available in online code.
To execute the
has_child queries, we will perform the following steps: