Using the has_child query/filter

ElasticSearch does not provide only simple documents, but it lets you define a hierarchy based on parent and child. The has_child query allows querying for parent documents of which the children verify some queries.

Getting ready

You need a working ElasticSearch cluster and the data populated with the populate script.

How to do it...

For executing the has_child query/filter, we need to perform the following steps:

1. We need to search the test-type parents of which the test-type2 children have a term in the field value as value1. We can create this kind of query as follows:

   curl -XPOST 'http://127.0.0.1:9200/test-index/test-type/_search' -d '{
       "query": {
               "has_child" : {
                   "type" : "test-type2",
                   "query" : {
                       "term" : {
                           "value" : "value1"
                       }
                   }
               }
           }
       }
   }'

2. If scoring is not important, it's better to reformulate the query as a...