From d844663f86c64aab678e1c9fe6ca5be089f95514 Mon Sep 17 00:00:00 2001
From: asahi <mikiyashiki@outlook.com>
Date: Tue, 29 Oct 2024 20:03:05 +0800
Subject: [PATCH] =?UTF-8?q?=E9=98=85=E8=AF=BBes=E6=96=87=E6=A1=A3?=
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---
 elastic search/elastic search.md | 123 +++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)

diff --git a/elastic search/elastic search.md b/elastic search/elastic search.md
index 597aa6d..f4615bf 100644
--- a/elastic search/elastic search.md	
+++ b/elastic search/elastic search.md	
@@ -484,6 +484,129 @@ DELETE /my-explicit-mappings-books
 删除索引将会永久删除其document、shards、元数据。
 
 
+### 全文本搜索和过滤
+如下示例展示了如何实现cook blog的搜索功能。
+#### 创建索引
+创建`cooking_blog`索引
+```
+PUT /cooking_blog
+```
+
+为索引定义mapping：
+```
+PUT /cooking_blog/_mapping
+{
+  "properties": {
+    "title": {
+      "type": "text",
+      "analyzer": "standard", 
+      "fields": { 
+        "keyword": {
+          "type": "keyword",
+          "ignore_above": 256 
+        }
+      }
+    },
+    "description": {
+      "type": "text",
+      "fields": {
+        "keyword": {
+          "type": "keyword"
+        }
+      }
+    },
+    "author": {
+      "type": "text",
+      "fields": {
+        "keyword": {
+          "type": "keyword"
+        }
+      }
+    },
+    "date": {
+      "type": "date",
+      "format": "yyyy-MM-dd"
+    },
+    "category": {
+      "type": "text",
+      "fields": {
+        "keyword": {
+          "type": "keyword"
+        }
+      }
+    },
+    "tags": {
+      "type": "text",
+      "fields": {
+        "keyword": {
+          "type": "keyword"
+        }
+      }
+    },
+    "rating": {
+      "type": "float"
+    }
+  }
+}
+```
+
+上述mapping定义含义如下：
+- 对于`text`类型的field，如果analyzer没有指定，那么会默认使用`standard` analyzer
+- 在上述示例中，使用了`multi fields`，将字段既作为`text`来进行全文搜索，又作为`keyword`来进行聚合和排序。在该字段上，既支持全文搜索，又支持青雀匹配和过滤。如果使用dynamic mapping，那么multi-fields将会自动被创建。
+- `ignore_above`不会索引`keyword`field中超过256个字符长度的值。默认情况下，keyword field其ignore_above的值为256
+
+> #### multi-field
+> 对同一个字段按不同的方式进行索引有时候很必要，对于multi-fields，一个字符串类型字段可以被映射到`text`类型用于全文索引，也可以被映射到`keyword`类型用作排序和聚合。
+>
+> 示例如下：
+> ```
+> PUT my-index-000001
+> {
+>   "mappings": {
+>    "properties": {
+>      "city": {
+>        "type": "text",
+>        "fields": {
+>          "raw": { 
+>            "type":  "keyword"
+>          }
+>        }
+>      }
+>    }
+>  }
+> }
+> 
+> PUT my-index-000001/_doc/1
+> {
+>   "city": "New York"
+> }
+>
+> PUT my-index-000001/_doc/2
+> {
+>   "city": "York"
+> }
+>
+> GET my-index-000001/_search
+> {
+>   "query": {
+>     "match": {
+>       "city": "york" 
+>     }
+>   },
+>   "sort": {
+>     "city.raw": "asc" 
+>   },
+>   "aggs": {
+>     "Cities": {
+>       "terms": {
+>         "field": "city.raw" 
+>       }
+>     }
+>   }
+> }
+> ```
+
+#### 将blog示例添加到索引中