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OpenSearch/docs/reference/query-dsl/joining-queries.asciidoc

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Docs: Reorganised the Query DSL docs into families and explaing query vs filter context
2015-06-03 19:59:22 -04:00
[[joining-queries]]
== Joining queries
Performing full SQL-style joins in a distributed system like Elasticsearch is
prohibitively expensive. Instead, Elasticsearch offers two forms of join
which are designed to scale horizontally.
<<query-dsl-nested-query,`nested` query>>::
Fix grammar issues in some docs This commit fixes some grammar issues in various docs. Closes #20751 Closes #20752 Closes #20754 Closes #20755
2016-10-05 08:54:32 -04:00
Documents may contain fields of type <<nested,`nested`>>. These
Docs: Reorganised the Query DSL docs into families and explaing query vs filter context
2015-06-03 19:59:22 -04:00
fields are used to index arrays of objects, where each object can be queried
(with the `nested` query) as an independent document.
<<query-dsl-has-child-query,`has_child`>> and <<query-dsl-has-parent-query,`has_parent`>> queries::
A <<mapping-parent-field,parent-child relationship>> can exist between two
document types within a single index. The `has_child` query returns parent
documents whose child documents match the specified query, while the
`has_parent` query returns child documents whose parent document matches the
specified query.
Also see the <<query-dsl-terms-lookup,terms-lookup mechanism>> in the `terms`
query, which allows you to build a `terms` query from values contained in
another document.
include::nested-query.asciidoc[]
include::has-child-query.asciidoc[]
include::has-parent-query.asciidoc[]
Cleanup ParentFieldMapper: * Remove remaining 1.x bwc logic. * Stop storing stored fields and indexed terms. The _parent field's only purpose is to support joins between parent and child type and only storing doc values is sufficient. * In the mapping the parent field mapper is now known under '{parent}#{child}' key, because this is the field the parent/child join uses too. * Added new sub fetch phase to lookup that _parent field from doc values field if that is required (before this was fetched from stored _parent field) * Removed the ability to query directly on `_parent` in the query dsl. Instead the `{parent}#{child}` field should be used. Under the hood a doc values query is used instead of a term query, because only doc values fields are stored now. * Added a new `parent_id` query to easily query child documents with a specific parent id without having to know what join field to use * Also in aggregations `_parent` field can't be used any more and `{parent}#{child}` field name should be used instead to aggregate directly on the _parent join field.
2016-01-17 16:49:07 -05:00
include::parent-id-query.asciidoc[]
Docs: Reorganised the Query DSL docs into families and explaing query vs filter context
2015-06-03 19:59:22 -04:00