Elasticsearch 7：数组

#Elasticsearch

官方文档：https://www.elastic.co/guide/en/elasticsearch/reference/7.2/array.html。

在 ES 中，没有专用的数组类型，任何字段都可以变成数组。

示例：

创建索引：

PUT student
{
  "mappings" : {
    "properties" : {
      "scores" : {
        "type" : "integer"
      }
    }
  }
}

使用 _bulk 创建文档，注意，文档2的 scores 是数组：

POST _bulk
{ "index" : { "_index" : "student", "_id" : "1" } }
{ "scores" : 80 }
{ "index" : { "_index" : "student", "_id" : "2" } }
{ "scores" : [80, 90] }

查询所有数据：

# 请求
GET student/_search

# 响应
{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "student",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "scores" : 80
        }
      },
      {
        "_index" : "student",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 1.0,
        "_source" : {
          "scores" : [
            80,
            90
          ]
        }
      }
    ]
  }
}

在查询时，命中数组的其中一个，就会认为是符合条件：

# 请求
GET student/_search
{
  "query": {
    "term": {
      "scores": 90
    }
  }
}

# 响应
{
  "took" : 487,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "student",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 1.0,
        "_source" : {
          "scores" : [
            80,
            90
          ]
        }
      }
    ]
  }
}

如何为文档1的scores字段添加一个值 ？可以这样：

POST student/_update_by_query
{
  "query": { 
    "match": {
      "_id": 1
    }
  },
  "script": {
    "source": "if (ctx._source.containsKey(\"scores\")) {if (ctx._source.scores instanceof List) ctx._source.scores.add(88); else ctx._source.scores = [ctx._source.scores, 88];} else {ctx._source.scores = [88]}"
  }
}

执行后重新查询：

# 请求
GET student/_search

# 响应
{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "student",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 1.0,
        "_source" : {
          "scores" : [
            80,
            90
          ]
        }
      },
      {
        "_index" : "student",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "scores" : [
            80,
            88
          ]
        }
      }
    ]
  }
}

关于 script 语法的介绍：

• https://www.elastic.co/guide/en/elasticsearch/reference/7.2/modules-scripting.html
• https://www.elastic.co/guide/en/elasticsearch/painless/7.2/painless-lang-spec.html

( 本文完 )