Indexing tree-like structures

Trees are everywhere. If you develop a shop application, you would probably have categories. If you look at the filesystem, the files and directories are arranged in tree-like structures. This book can also be represented as a tree: chapters contain topics and topics are divided into subtopics. As you can imagine, Elasticsearch is also capable of indexing tree-like structures. Let's check how we can navigate through this type of data using path_analyzer.

Data structure

First, let's create a simple index structure by using the following lines of code:

curl -XPUT 'localhost:9200/path' -d '{
  "settings" : {
    "index" : {
      "analysis" : {
        "analyzer" : {
          "path_analyzer" : { "tokenizer" : "path_hierarchy" }
        }
      }
    }
  },
  "mappings" : {
    "category" : {
      "properties" : {
        "category" : {
          "type" : "string",
          "fields" : {
            "name" : { "type" : "string","index" : "not_analyzed" },
      ...