How to use an Array mapping in ES?

Question

I wanted to create a mapping for movies that look like:

{    title: "The Artist",    genres: ["Drama", "Comedy"] } 

In the ElasticSearch documentation I see this example:

"properties" : {         "message" : {"type" : "string"},         "tags" : {"type" : "string", "index_name" : "tag"},         ...   } 

However, now I am confused.. What I expected to see was:

 "properties" : {      "message" : {"type" : "string"},       "tags" : {"type" : "array"}   } 

So, why does the example just provide a reference to another index? How would I define that "tags" index? Or, when would I use that Array mapping?

Answer 1

So ElasticSearch doesn't need to specify that a mapping is an array. You can treat any mapping as an array by using square brackets:

{     title: ["The Artist", "Formerly known as Prince" ],     genres: ["Drama", "Comedy"],     ... } 

See the last sentence on the page:

We could, of course, name the field as tag and skip the index_name all together

The "index_name" mapping just allows you to define an alias in the plural form of tag -> tags.