document mapping

只能创建index时手动建立mapping，或者新增field mapping，但是不能修改 field mapping

查看mapping

GET /index/_mapping/type

"index"参数－的分词情况

值：2017-08-15

• analyzed :会拆分成　2017,01,15等进行索引

• not_analyzed:不分词，2017-08-15作为整体索引

• no　不分词不索引（不索引也就是不参与搜索）

analyzer参数-分词器

核心的数据类型 type

string: text , keyword
byte，short，integer，long
float，double
boolean
date

示例

手动创建mapping

PUT /website
{
  "mappings": {
    "article": {
      "properties": {
        "author_id": {
          "type": "long"
        },
        "title": {
          "type": "text",
          "analyzer": "english"
        },
        "content": {
          "type": "text"
        },
        "post_date": {
          "type": "date"
        },
        "publisher_id": {
          "type": "text",
          "index": "not_analyzed"
        }
      }
    }
  }
}

修改mapping 会报错

为什么不能修改一个字段的type？原因是一个字段的类型修改以后，那么该字段的所有数据都需要重新索引。Elasticsearch底层使用的是lucene库，字段类型修改以后索引和搜索要涉及分词方式等操作，不允许修改类型在我看来是符合lucene机制的。

PUT /website
{
  "mappings": {
    "article": {
      "properties": {
        "author_id": {
          "type": "text"
        }
      }
    }
  }
}

报错:

{
  "error": {
    "root_cause": [
      {
        "type": "index_already_exists_exception",
        "reason": "index [website/co1dgJ-uTYGBEEOOL8GsQQ] already exists",
        "index_uuid": "co1dgJ-uTYGBEEOOL8GsQQ",
        "index": "website"
      }
    ],
    "type": "index_already_exists_exception",
    "reason": "index [website/co1dgJ-uTYGBEEOOL8GsQQ] already exists",
    "index_uuid": "co1dgJ-uTYGBEEOOL8GsQQ",
    "index": "website"
  },
  "status": 400
}

新增field: ok

PUT /website/_mapping/article
{
  "properties" : {
    "new_field" : {
      "type" :    "string",
      "index":    "not_analyzed"
    }
  }
}

资料：

Elasticsearch索引mapping的写入、查看与修改