fos_elastica:
    clients:
        default:
            url: http://localhost:9200
    indexes:
        test_index:
            client: default
            types:
                parent_field:
                    mappings:
                        text: ~
                    persistence:
                        driver: orm
                        model: foo_model
                child_field:
                    mappings:
                        text: ~
                    persistence:
                        driver: orm
                        model: foo_model
                    _parent: { type: "parent_field", property: "parent" }