# _uid field 原文链接 : [https://www.elastic.co/guide/en/elasticsearch/reference/5.3/mapping-uid-field.html](https://www.elastic.co/guide/en/elasticsearch/reference/5.3/mapping-uid-field.html) 译文链接 : [http://www.apache.wiki/display/Elasticsearch/_uid+field](http://www.apache.wiki/display/Elasticsearch/_uid+field) 贡献者 : [朱彦安](/display/~zhuyanan)，[ApacheCN](/display/~apachecn)，[Apache中文网](/display/~apachechina) 每个索引的文档都与一个 **[_type](https://www.elastic.co/guide/en/elasticsearch/reference/5.3/mapping-type-field.html)**（请参见“**[Mapping Types](https://www.elastic.co/guide/en/elasticsearch/reference/5.3/mapping.html#mapping-type)[edit](https://github.com/elastic/elasticsearch/edit/5.3/docs/reference/mapping.asciidoc)**”一节）和一个 **[_id](https://www.elastic.co/guide/en/elasticsearch/reference/5.3/mapping-id-field.html) **相关联。 这些值组合为 **{type}＃{id} **并作为 **_uid **字段编入索引。 该 **_uid**字段的值可以在 **queries**（查询），**aggregations**（聚合），**scripts**（脚本）以及 **sorting**（排序）时访问 :  ``` # Example documents curl -XPUT 'localhost:9200/my_index/my_type/1?pretty' -H 'Content-Type: application/json' -d' { "text": "Document with ID 1" } ' curl -XPUT 'localhost:9200/my_index/my_type/2?refresh=true&pretty' -H 'Content-Type: application/json' -d' { "text": "Document with ID 2" } ' curl -XGET 'localhost:9200/my_index/_search?pretty' -H 'Content-Type: application/json' -d' { "query": { "terms": { "_uid": [ "my_type#1", "my_type#2" ] # 1 } }, "aggs": { "UIDs": { "terms": { "field": "_uid", # 2 "size": 10 } } }, "sort": [ { "_uid": { # 3 "order": "desc" } } ], "script_fields": { "UID": { "script": { "lang": "painless", "inline": "doc['_uid']" # 4 } } } } ' ``` | 1 | 在 **_uid** 字段上查询 (也可以参考 **[ids query](https://www.elastic.co/guide/en/elasticsearch/reference/5.3/query-dsl-ids-query.html)**) | | 2 | 在 **_uid** 字段上聚合 | | 3 | 在 **_uid** 字段上排序 | | 4 | 在脚本中访问 **_uid** 字段 |