KeyWord · Elasticsearch 5.4 中文文檔

# KeyWord 原文鏈接 : [https://www.elastic.co/guide/en/elasticsearch/reference/current/keyword.html#keyword](https://www.elastic.co/guide/en/elasticsearch/reference/current/keyword.html#keyword) 譯文鏈接 : [KeyWord](/display/Elasticsearch/KeyWord) 貢獻者 : [彭秋源](/display/~pengqiuyuan)，[ApacheCN](/display/~apachecn)，[Apache中文網](/display/~apachechina) ## Keyword datatype 用于索引結構化的數據的字段，比如 email 地址、主機名、狀態碼、郵政編碼或者標簽，通常用于過濾（查找所有狀態是 published 的博客文章）、排序、聚合。`keyword?`字段只能通過精確值來搜索。如果需要索引全文內容，比如 email 體或者產品描述，那么你可能需要使用?`text?`字段。 ``` curl -XPUT 'localhost:9200/my_index?pretty' -d' { "mappings": { "my_type": { "properties": { "tags": { "type": "keyword" } } } } }' ``` ## Parameters for keyword fields keyword 字段接受的參數 | [`boost`](https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-boost.html "boost") | Mapping field-level query time boosting. Accepts a floating point number, defaults to?`1.0`. | | [`doc_values`](https://www.elastic.co/guide/en/elasticsearch/reference/current/doc-values.html "doc_values") | Should the field be stored on disk in a column-stride fashion, so that it can later be used for sorting, aggregations, or scripting? Accepts?`true`(default) or?`false`. | | [`eager_global_ordinals`](https://www.elastic.co/guide/en/elasticsearch/reference/current/fielddata.html#global-ordinals "Global ordinals") | ?Should global ordinals be loaded eagerly on refresh? Accepts?`true`?or?`false`?(default). Enabling this is a good idea on fields that are frequently used for terms aggregations. | | [`fields`](https://www.elastic.co/guide/en/elasticsearch/reference/current/multi-fields.html "fields") | Multi-fields allow the same string value to be indexed in multiple ways for different purposes, such as one field for search and a multi-field for sorting and aggregations. | | [`ignore_above`](https://www.elastic.co/guide/en/elasticsearch/reference/current/ignore-above.html "ignore_above") | Do not index any string longer than this value. Defaults to?`2147483647`?so that all values would be accepted. | | [`include_in_all`](https://www.elastic.co/guide/en/elasticsearch/reference/current/include-in-all.html "include_in_all") | Whether or not the field value should be included in the?[`_all`](https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-all-field.html "_all field")?field? Accepts?`true`?or?`false`. Defaults to?`false`?if?[`index`](https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-index.html "index")?is set to?`no`, or if a parent?[`object`](https://www.elastic.co/guide/en/elasticsearch/reference/current/object.html "Object datatype")?field sets?`include_in_all`?to?`false`. Otherwise defaults to?`true`. | | [`index`](https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-index.html "index") | Should the field be searchable? Accepts?`true`?(default) or?`false`. | | [`index_options`](https://www.elastic.co/guide/en/elasticsearch/reference/current/index-options.html "index_options") | What information should be stored in the index, for scoring purposes. Defaults to?`docs`?but can also be set to?`freqs`?to take term frequency into account when computing scores. | | [`norms`](https://www.elastic.co/guide/en/elasticsearch/reference/current/norms.html "norms") | Whether field-length should be taken into account when scoring queries. Accepts?`true`?or?`false`?(default). | | [`null_value`](https://www.elastic.co/guide/en/elasticsearch/reference/current/null-value.html "null_value") | Accepts a string value which is substituted for any explicit?`null`?values. Defaults to?`null`, which means the field is treated as missing. | | [`store`](https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-store.html "store") | Whether the field value should be stored and retrievable separately from the?[`_source`](https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-source-field.html "_source field")?field. Accepts?`true`?or?`false`?(default). | | [`similarity`](https://www.elastic.co/guide/en/elasticsearch/reference/current/similarity.html "similarity") | Which scoring algorithm or?_similarity_?should be used. Defaults to?`BM25`. | | [`normalizer`](https://www.elastic.co/guide/en/elasticsearch/reference/current/normalizer.html "normalizer") | [experimental]??This functionality is experimental and may be changed or removed completely in a future release. Elastic will take a best effort approach to fix any issues, but experimental features are not subject to the support SLA of official GA features.How to pre-process the keyword prior to indexing. Defaults to?`null`, meaning the keyword is kept as-is. | 注意 2.x版本導入的索引不支持 `keyword` 。它們會嘗試將 `keyword` 降級到 `string` 。這允許你將新映射和舊映射合并。長期索引在升級到6.x之前必須重新創建，但是映射降級允許你根據自己的安排來進行重新創建。