Array Type

JSON documents allow to define an array (list) of fields or objects. Mapping array types could not be simpler since arrays gets automatically detected and mapping them can be done either with Core Types or Object Type mappings. For example, the following JSON defines several arrays:

{
    "tweet" : {
        "message" : "some arrays in this tweet...",
        "tags" : ["elasticsearch", "wow"],
        "lists" : [
            {
                "name" : "prog_list",
                "description" : "programming list"
            },
            {
                "name" : "cool_list",
                "description" : "cool stuff list"
            }
        ]
    }
}

The above JSON has the tags property defining a list of a simple string type, and the lists property is an object type array. Here is a sample explicit mapping:

{
    "tweet" : {
        "properties" : {
            "message" : {"type" : "string"},
            "tags" : {"type" : "string", "index_name" : "tag"},
            "lists" : {
                "properties" : {
                    "name" : {"type" : "string"},
                    "description" : {"type" : "string"}
                }
            }
        }
    }
}

The fact that array types are automatically support can be shown by the fact that the following JSON document is perfectly fine:

{
    "tweet" : {
        "message" : "some arrays in this tweet...",
        "tags" : "elasticsearch",
        "lists" : {
            "name" : "prog_list",
            "description" : "programming list"
        }
    }
}

Note also, that thanks to the fact that we used the index_name to use the non plural form (tag instead of tags), we can actually refer to the field using the index_name as well. For example, we can execute a query using tweet.tags:wow or tweet.tag:wow. We could, of course, name the field as tag and skip the index_name all together).