Book Image

ElasticSearch Cookbook

By : Alberto Paro
Book Image

ElasticSearch Cookbook

By: Alberto Paro

Overview of this book

ElasticSearch is one of the most promising NoSQL technologies available and is built to provide a scalable search solution with built-in support for near real-time search and multi-tenancy. This practical guide is a complete reference for using ElasticSearch and covers 360 degrees of the ElasticSearch ecosystem. We will get started by showing you how to choose the correct transport layer, communicate with the server, and create custom internal actions for boosting tailored needs. Starting with the basics of the ElasticSearch architecture and how to efficiently index, search, and execute analytics on it, you will learn how to extend ElasticSearch by scripting and monitoring its behaviour. Step-by-step, this book will help you to improve your ability to manage data in indexing with more tailored mappings, along with searching and executing analytics with facets. The topics explored in the book also cover how to integrate ElasticSearch with Python and Java applications. This comprehensive guide will allow you to master storing, searching, and analyzing data with ElasticSearch.
Table of Contents (19 chapters)
ElasticSearch Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Managing nested objects


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

If we consider the previous order example, it's not possible to disguise an item name and its quantity with the same query. We need to index them in different elements and when we join them. This entire trip is managed by nested objects and nested queries.

Getting ready

You need a working ElasticSearch cluster.

How to do it...

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

From the example of the Mapping an object recipe, we can change the type from object to nested as shown in the following code:

{
  "order" : {
    "properties" : {
      "id" : {"type" : "string", 
      "store" : "yes", "index":"not_analyzed"},
   ...