DOCSP-45205 Multikey Indexes

source/includes/indexes/multikey.rb

@@ -0,0 +1,37 @@
+require 'mongo'
+
+# Replace the placeholders with your credentials
+uri = "<connection string>"
+
+# Sets the server_api field of the options object to Stable API version 1
+options = { server_api: { version: "1" }}
+
+# Creates a new client and connect to the server
+client = Mongo::Client.new(uri, options)
+
+# start-sample-data
+database = client.use('sample_mflix')
+collection = database[:movies]
+# end-sample-data
+
+# Creates an index on the "cast" field
+# start-index-multikey
+collection.indexes.create_one({ cast: 1 })
+# end-index-multikey
+
+# Finds a document with the specified cast members by using the newly created index
+# start-index-multikey-query
+filter = { cast: { '$all' => ['Aamir Khan', 'Kajol'] } }
+doc = collection.find(filter).first
+
+if doc
+  puts doc.to_json
+else
+  puts "No document found"
+end
+# end-index-multikey-query
+
+# Lists all indexes on the collection
+# start-check-multikey-index
+puts collection.indexes.collect(&:to_json)
+# end-check-multikey-index

source/indexes.txt

@@ -21,10 +21,10 @@ Optimize Queries by Using Indexes
 .. toctree::
    :titlesonly:
    :maxdepth: 1
-   
+
    Single Field </indexes/single-field-index>
    Compound </indexes/compound-index>
-..   Multikey </indexes/multikey-index>
+   Multikey </indexes/multikey-index>
 ..   Atlas Search </indexes/atlas-search-index>
 
 Overview

source/indexes/multikey-index.txt

@@ -0,0 +1,123 @@
+.. _ruby-multikey-index:
+
+================
+Multikey Indexes
+================
+
+.. contents:: On this page
+   :local:
+   :backlinks: none
+   :depth: 2
+   :class: singlecol
+
+.. facet::
+   :name: genre
+   :values: reference
+
+.. meta::
+   :keywords: index, query, optimization, efficiency
+
+Overview
+--------
+
+**Multikey indexes** are indexes that improve the performance of queries
+on array-valued fields. You can create a multikey index on a collection
+by using the ``create_one`` method and the same syntax that you use to create 
+a :ref:`single field index <ruby-single-field-index>`.
+
+
+When creating a multikey index, you must specify the following details:
+
+- The fields on which to create the index
+
+- The sort order for each field (ascending or descending)
+
+Sample Data
+~~~~~~~~~~~
+
+The examples in this guide use the ``movies`` collection in the
+``sample_mflix`` database from the :atlas:`Atlas sample datasets
+</sample-data>`. To access this collection from your {+language+} 
+application, create a ``Mongo::Client`` object that connects to
+an Atlas cluster and assign the following values to your ``database`` 
+and ``collection`` variables: 
+
+.. literalinclude:: /includes/indexes/single-field.rb
+   :start-after: start-sample-data
+   :end-before: end-sample-data
+   :language: ruby
+   :copyable:
+
+To learn how to create a free MongoDB Atlas cluster and
+load the sample datasets, see the :atlas:`Get Started with Atlas
+</getting-started>` guide.
+
+Create a Multikey Index
+-----------------------
+
+Use the ``create_one`` method to create a multikey index. The following example 
+creates an index in ascending order on the ``cast`` field:
+
+.. literalinclude:: /includes/indexes/multikey.rb
+   :start-after: start-index-multikey
+   :end-before: end-index-multikey
+   :language: ruby
+   :copyable:
+
+Verify Index Creation
+---------------------
+
+You can verify that the index was created by listing the indexes in the 
+collection. You should see an index for ``cast`` in the list, as shown 
+in the following output:
+
+.. io-code-block::
+   :copyable: true
+
+   .. input:: /includes/indexes/multikey.rb
+      :start-after: start-check-multikey-index
+      :end-before: end-check-multikey-index
+      :language: ruby
+
+   .. output::
+      :visible: true
+
+      {"v": 2, "key": {"cast": 1}, "name": "cast_1"}
+
+Example Query
+-------------
+
+The following is an example of a query that is covered by the index
+created on the ``cast`` field:
+
+.. io-code-block::
+   :copyable: true
+
+   .. input:: /includes/indexes/multikey.rb
+      :start-after: start-index-multikey-query
+      :end-before: end-index-multikey-query
+      :language: ruby
+
+   .. output::
+      :visible: false
+
+      {"_id":...,"title":"Fanaa",...,"cast": ["Aamir Khan", "Kajol", "Rishi Kapoor", "Tabu"],...}
+
+Additional Information
+----------------------
+
+To view runnable examples that demonstrate how to manage indexes, see
+:ref:`ruby-indexes`.
+
+To learn more about multikey indexes, see :manual:`Multikey
+Indexes </core/indexes/index-types/index-multikey/>` in the {+mdb-server+} manual.
+
+API Documentation
+~~~~~~~~~~~~~~~~~
+
+To learn more about any of the methods discussed in this guide, see the
+following API documentation:
+
+- `indexes <{+api-root+}/Mongo/Collection.html#indexes-instance_method>`__
+- `create_one <{+api-root+}/Mongo/Index/View.html>`__
+- `find <{+api-root+}/Mongo/Collection.html#find-instance_method>`__