Elasticsearch索引的父子關係(index parent-child)

＃Elasticsearch容許給文檔創建父子關係，這篇博客介紹文檔的父子關係是如何映射的(Parent-Child Mapping)、如何索引父子文檔(Indexing Parents and Children)、如何經過子文檔查詢父文檔 
(Finding Parents by Their Children)、如何經過父文檔查詢子文檔(Finding Children by Their Parents)。

1、父子文檔的mapping

創建文檔的父子關係最重要的一步是在建立索引的時候在mapping中聲明哪一個是父文檔哪一個是子文檔。官網文檔給了一個公司在不少城市的分支(branch)和每一個分支有相關員工(employee)的例子，若是想把員工和他們工做的分公司關聯起來，咱們須要告訴Elasticsearch文檔之間的父子關係，這裏employee是child type,branch是parent type，在mapping中聲明：

curl -XPUT  "http://192.168.0.224:9200/company" -d '
{
  "mappings": {
    "branch": {},
    "employee": {
      "_parent": {
        "type": "branch"
      }
    }
  }
}
'

 

這樣咱們建立了一個索引，並制定了2個type和它們之間的父子關係.

2、父子文檔的索引

2.1索引父文檔

索引父文檔和索引通常的文檔沒有任何區別。 
準備幾條公司的數據，存在company.json文件中：

{ "index": { "_id": "london" }}
{ "name": "London Westminster", "city": "London", "country": "UK" }
{ "index": { "_id": "liverpool" }}
{ "name": "Liverpool Central", "city": "Liverpool", "country": "UK" }
{ "index": { "_id": "paris" }}
{ "name": "Champs Élysées", "city": "Paris", "country": "France" }

 

使用Bulk端點批量導入：

curl -XPOST "http://192.168.0.224:9200/company/branch/_bulk?pretty" --data-binary @company.json

 

2.2索引子文檔

索引子文檔須要制定子文檔的父ID，給子文檔的每條文檔設置parent屬性的value爲父文檔id便可：

curl -XPUT "http://192.168.0.224:9200/company/employee/1?parent=london&pretty" -d '
{
  "name":  "Alice Smith",
  "dob":   "1970-10-24",
  "hobby": "hiking"
}
'

 

執行bulk命令：

curl -XPOST "http://192.168.0.224:9200/company/employee/_bulk?pretty" --data-binary @employee.json

 

3、經過子文檔查詢父文檔

搜索含有1980年之後出生的employee的branch：

curl -XGET "http://192.168.0.224:9200/company/branch/_search?pretty" -d '
{           
  "query": {      
    "has_child": {       
      "type": "employee",
      "query": {  
        "range": {
          "dob": {             
            "gte": "1980-01-01"
          }
        }
      }
    }
  }
}
'
{
  "took" : 19,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "failed" : 0
  },
  "hits" : {
    "total" : 2,
    "max_score" : 1.0,
    "hits" : [ {
      "_index" : "company",
      "_type" : "branch",
      "_id" : "paris",
      "_score" : 1.0,
      "_source" : {
        "name" : "Champs Élysées",
        "city" : "Paris",
        "country" : "France"
      }
    }, {
      "_index" : "company",
      "_type" : "branch",
      "_id" : "london",
      "_score" : 1.0,
      "_source" : {
        "name" : "London Westminster",
        "city" : "London",
        "country" : "UK"
      }
    } ]
  }
}

 

查詢name中含有「Alice Smith」的branch:

curl -XGET "http://192.168.0.224:9200/company/branch/_search?pretty" -d '
{
  "query": {
    "has_child": {
      "type":       "employee",
      "score_mode": "max",
      "query": {
        "match": {
          "name": "Alice Smith"
        }
      }
    }
  }
}'



{
  "took" : 20,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "failed" : 0
  },
  "hits" : {
    "total" : 2,
    "max_score" : 1.2422675,
    "hits" : [ {
      "_index" : "company",
      "_type" : "branch",
      "_id" : "london",
      "_score" : 1.2422675,
      "_source" : {
        "name" : "London Westminster",
        "city" : "London",
        "country" : "UK"
      }
    }, {
      "_index" : "company",
      "_type" : "branch",
      "_id" : "liverpool",
      "_score" : 0.30617762,
      "_source" : {
        "name" : "Liverpool Central",
        "city" : "Liverpool",
        "country" : "UK"
      }
    } ]
  }
}

 

搜索最少含有2個employee的branch：

curl -XGET "http://192.168.0.224:9200/company/branch/_search?pretty" -d '{
"query": {
    "has_child": {
      "type":         "employee",
      "min_children": 2,
      "query": {
        "match_all": {}
      }
    }
  }
}
'
{
  "took" : 17,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "failed" : 0
  },
  "hits" : {
    "total" : 1,
    "max_score" : 1.0,
    "hits" : [ {
      "_index" : "company",
      "_type" : "branch",
      "_id" : "london",
      "_score" : 1.0,
      "_source" : {
        "name" : "London Westminster",
        "city" : "London",
        "country" : "UK"
      }
    } ]
  }
}

 

4、經過父文檔查詢子文檔

搜搜工做在UK的employee：

curl -XGET "http://192.168.0.224:9200/company/employee/_search?pretty" -d '{           
  "query": {       
    "has_parent": {    
      "type": "branch", 
      "query": {  
        "match": {       
          "country": "UK"
        }
      }
    }
  }
}'

{
  "took" : 15,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "failed" : 0
  },
  "hits" : {
    "total" : 3,
    "max_score" : 1.0,
    "hits" : [ {
      "_index" : "company",
      "_type" : "employee",
      "_id" : "3",
      "_score" : 1.0,
      "_parent" : "liverpool",
      "_routing" : "liverpool",
      "_source" : {
        "name" : "Barry Smith",
        "dob" : "1979-04-01",
        "hobby" : "hiking"
      }
    }, {
      "_index" : "company",
      "_type" : "employee",
      "_id" : "1",
      "_score" : 1.0,
      "_parent" : "london",
      "_routing" : "london",
      "_source" : {
        "name" : "Alice Smith",
        "dob" : "1970-10-24",
        "hobby" : "hiking"
      }
    }, {
      "_index" : "company",
      "_type" : "employee",
      "_id" : "2",
      "_score" : 1.0,
      "_parent" : "london",
      "_routing" : "london",
      "_source" : {
        "name" : "Mark Thomas",
        "dob" : "1982-05-16",
        "hobby" : "diving"
      }
    } ]
  }
}