Managing nested objects

There is a special type of embedded object, the nested one. This resolves a problem related to Lucene indexing architecture, in which all the fields of embedded objects are viewed as a single object. During search, in Lucene, it is not possible to distinguish values between different embedded objects in the same multivalued array.

If we consider the previous order example, it's not possible to distinguish an item name and its quantity with the same query, as Lucene puts them in the same Lucene document object. We need to index them in different documents and then join them. This "entire trip" is managed by nested objects and nested queries.

Getting ready

You need an up-and-running Elasticsearch installation as we described in the Downloading and installing Elasticsearch recipe in Chapter 2, Downloading and Setup.

How to do it...

A nested object is defined as the standard object with the type nested.

From the example in the Mapping an object recipe, we can change the type...