简单分析器

只要找到非字母字符，例如空格、标点符号或一个或多个数字， simple分析器就会将文本划分为可搜索术语（词元）。它将所有文本转换为小写。

如果您选择 Refine Your Index， Atlas用户界面会在 Index Configurations 部分中显示标题为 View text analysis of your selected index configuration 的部分。如果展开此部分， Atlas用户界面会显示 simple分析器为每个示例字符串生成的索引和搜索词元。当您在Atlas用户界面Visual Editor 中创建或编辑索引时，您可以看到 simple分析器为内置示例文档和查询字符串创建的词元。

重要

MongoDB Search 不会对分析器词元大小超过 32766 字节的字符串字段索引。如果使用关键字分析器，则不会对超过 32766 字节的字符串字段编制索引。

例子

以下示例索引定义使用title simple分析器指定 sample_mflix.movies集合中的字段上的索引。要跟随此示例，请在集群上加载示例数据，并使用mongosh 或导航到Atlas用户界面中的Create a Search Index 页面，按照创建MongoDB搜索索引教程中的步骤操作。

然后，使用 movies 集合作为数据源，按照示例过程从 mongosh 或 Atlas 用户界面 Visual Editor 或 JSON editor 创建索引。

➤ 使用选择语言下拉菜单为此页面上的示例设立界面。

单击 Refine Your Index 配置索引。
在 Index Configurations 部分中，将 Dynamic Mapping 切换为 off。
在 Field Mappings 部分中，单击 Add Field 打开 Add Field Mapping 窗口。
单击 Customized Configuration（连接）。
从 Field Name 下拉列表中选择 title。
单击 Data Type 下拉列表并选择 String（如果尚未选择）。

展开 String Properties 并进行以下更改：

索引分析器	从下拉列表中选择 `lucene.simple`。
Search Analyzer	从下拉列表中选择 `lucene.simple`。
索引选项	使用默认 `offsets`。
Store	使用默认 `true`。
忽略以上内容	保留默认设置。
规范	使用默认 `include`。

单击 Add（连接）。
单击 Save Changes（连接）。
单击 Create Search Index（连接）。

将默认索引定义替换为以下索引定义。

{
  "mappings": {
    "fields": {
      "title": {
        "type": "string",
        "analyzer": "lucene.simple"
      }
    }
  }
}

单击 Next（连接）。
单击 Create Search Index（连接）。

1 db.movies.createSearchIndex(
2   "default",
3     {
4       "mappings": {
5         "fields": {
6           "title": {
7             "type": "string",
8             "analyzer": "lucene.simple"
9           }
10         }
11       }
12     }
13 )

以下查询在title字段中搜索词语lion ，并将输出限制为五个结果。

单击索引的 Query 按钮。
单击 Edit Query 编辑查询。
单击查询栏上的并选择数据库和集合。

将默认查询替换为以下内容，然后单击 Find：

[
  {
    "$search": {
      "text": {
        "query": "lion",
        "path": "title"
      }
    }
  }
]

SCORE: 3.9090898036956787  _id:  "573a13cbf29313caabd8135d"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   fullplot: "According to the legend of the Shangaan, white lions are the messenger…"
   genres: Array (2)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-09-02 00:45:38.833000000"
   num_mflix_comments: 2
   plot: "According to the legend of the Shangaan, white lions are the messenger…"
   poster: "https://m.media-amazon.com/images/M/MV5BMTcwMTAyMzg5OV5BMl5BanBnXkFtZT…"
   rated: "PG"
   released: 2010-02-19T00:00:00.000+00:00
   runtime: 88
   title: "White Lion"
   type: "movie"
   writers: Array (3)
   year: 2010
SCORE: 3.363236427307129    _id:  "573a1399f29313caabcee7fc"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (2)
   fullplot: "A young lion Prince is cast out of his pride by his cruel uncle, who c…"
   genres: Array (3)
   imdb: Object
   languages: Array (4)
   lastupdated: "2015-08-31 00:04:32.670000000"
   metacritic: 83
   num_mflix_comments: 132
   plot: "Lion cub and future king Simba searches for his identity. His eagernes…"
   poster: "https://m.media-amazon.com/images/M/MV5BYTYxNGMyZTYtMjE3MS00MzNjLWFjNm…"
   rated: "G"
   released: 1994-06-24T00:00:00.000+00:00
   runtime: 89
   title: "The Lion King"
   tomatoes: Object
   type: "movie"
   writers: Array (29)
   year: 1994
SCORE: 3.363236427307129    _id:  "573a13a9f29313caabd1f600"
   awards: Object
   cast: Array (4)
   countries: Array (2)
   directors: Array (1)
   fullplot: "Timon and Pumbaa start to watch the original Lion King movie, but Timo…"
   genres: Array (3)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-09-14 00:01:14.313000000"
   num_mflix_comments: 0
   plot: "Timon the meerkat and Pumbaa the warthog retell the story of The Lion …"
   poster: "https://m.media-amazon.com/images/M/MV5BYzg2N2Y1ODYtY2QyMi00ZDAyLWE3MT…"
   rated: "G"
   released: 2004-02-10T00:00:00.000+00:00
   runtime: 77
   title: "The Lion King 1 1/2"
   tomatoes: Object
   type: "movie"
   writers: Array (5)
   year: 2004
SCORE: 3.363236427307129    _id:  "573a13abf29313caabd24af6"
   awards: Object
   cast: Array (4)
   countries: Array (2)
   directors: Array (1)
   fullplot: "Timon and Pumbaa start to watch the original Lion King movie, but Timo…"
   genres: Array (3)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-08-31 05:44:38.700000000"
   num_mflix_comments: 0
   plot: "Timon the meerkat and Pumbaa the warthog retell the story of The Lion …"
   poster: "https://m.media-amazon.com/images/M/MV5BYzg2N2Y1ODYtY2QyMi00ZDAyLWE3MT…"
   rated: "G"
   released: 2004-02-10T00:00:00.000+00:00
   runtime: 77
   title: "The Lion King 1 1/2"
   tomatoes: Object
   type: "movie"
   writers: Array (5)
   year: 2004
SCORE: 2.9511470794677734   _id:  "573a1396f29313caabce366e"
   awards: Object
   cast: Array (4)
   countries: Array (2)
   directors: Array (1)
   fullplot: "Christmas 1183--an aging and conniving King Henry II plans a reunion w…"
   genres: Array (2)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-09-17 01:39:32.220000000"
   num_mflix_comments: 0
   plot: "1183 AD: King Henry II's three sons all want to inherit the throne, bu…"
   poster: "https://m.media-amazon.com/images/M/MV5BMTkzNzYyMzA5N15BMl5BanBnXkFtZT…"
   rated: "PG"
   released: 1968-10-30T00:00:00.000+00:00
   runtime: 134
   title: "The Lion in Winter"
   tomatoes: Object
   type: "movie"
   writers: Array (2)
   year: 1968
SCORE: 2.9511470794677734   _id:  "573a13c1f29313caabd63be7"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   genres: Array (1)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-04-24 02:38:23.767000000"
   num_mflix_comments: 0
   poster: "https://m.media-amazon.com/images/M/MV5BMTg4Mzg4NDk5MF5BMl5BanBnXkFtZT…"
   released: 2009-11-06T00:00:00.000+00:00
   runtime: 92
   title: "Son of a Lion"
   tomatoes: Object
   type: "movie"
   writers: Array (1)
   year: 2007
SCORE: 2.9511470794677734   _id:  "573a13dbf29313caabdaf30d"
   awards: Object
   cast: Array (4)
   countries: Array (2)
   directors: Array (1)
   fullplot: "Neo-Nazi falls in love with a woman who has a black son and finds hims…"
   genres: Array (2)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-08-15 00:13:18.457000000"
   num_mflix_comments: 0
   plot: "Neo-Nazi falls in love with a woman who has a black son and finds hims…"
   poster: "https://m.media-amazon.com/images/M/MV5BY2M4ZjI5NmMtZjcyNy00NWU3LWI2Zj…"
   released: 2013-10-18T00:00:00.000+00:00
   runtime: 104
   title: "Heart of a Lion"
   tomatoes: Object
   type: "movie"
   writers: Array (1)
   year: 2013
SCORE: 2.629019260406494    _id:  "573a1397f29313caabce5e62"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   fullplot: "At the beginning of the 20th century an American woman is abducted in …"
   genres: Array (3)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-09-02 00:17:16.943000000"
   num_mflix_comments: 2
   plot: "At the beginning of the 20th century an American woman is abducted in …"
   poster: "https://m.media-amazon.com/images/M/MV5BYTNhODI4NWYtYzc1Zi00OGIxLTk5ZW…"
   rated: "PG"
   released: 1975-10-26T00:00:00.000+00:00
   runtime: 119
   title: "The Wind and the Lion"
   tomatoes: Object
   type: "movie"
   writers: Array (1)
   year: 1975
SCORE: 2.629019260406494    _id:  "573a13ebf29313caabdcfc8d"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   fullplot: "A documentary on young actress, Marianna Palka, as she confronts her r…"
   genres: Array (3)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-09-03 00:37:45.227000000"
   num_mflix_comments: 0
   plot: "A documentary on young actress, Marianna Palka, as she confronts her r…"
   poster: "https://m.media-amazon.com/images/M/MV5BMTgzMTc2OTg2N15BMl5BanBnXkFtZT…"
   released: 2014-01-18T00:00:00.000+00:00
   runtime: 15
   title: "The Lion's Mouth Opens"
   type: "movie"
   writers: Array (1)
   year: 2014
SCORE: 2.3702940940856934   _id:  "573a139af29313caabcf0ccd"
   awards: Object
   cast: Array (4)
   countries: Array (2)
   directors: Array (2)
   fullplot: "Simba and Nala have a daughter, Kiara. Timon and Pumbaa are assigned t…"
   genres: Array (3)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-08-24 00:49:09.900000000"
   num_mflix_comments: 0
   plot: "Simba's daughter is the key to a resolution of a bitter feud between S…"
   poster: "https://m.media-amazon.com/images/M/MV5BY2Y3MTk2MDgtOTc1Yy00ZmFjLThlNT…"
   rated: "G"
   released: 1998-10-27T00:00:00.000+00:00
   runtime: 81
   title: "The Lion King 2: Simba's Pride"
   tomatoes: Object
   type: "movie"
   writers: Array (10)
   year: 1998

1 db.movies.aggregate([
2   {
3     "$search": {
4       "text": {
5          "query": "lion",
6          "path": "title"
7       }
8     }
9   },
10   {
11     "$limit": 5
12   },
13   {
14     "$project": {
15       "_id": 0,
16       "title": 1
17     }
18   }
19 ])

[
  { title: 'White Lion' },
  { title: 'The Lion King' },
  { title: 'The Lion King 1 1/2' },
  { title: 'The Lion King 1 1/2' },
  { title: 'Lion's Den' },
]

MongoDB Search 通过使用 lucene.simple分析器对 title字段中的文本执行以下操作来返回这些文档：

将文本转换为小写。
通过在存在非字母字符的位置分割文本来创建单独的词元。

下表显示了MongoDB Search 使用简单分析器以及标准分析器和空格分析器为结果中的文档创建的词元：

标题	简单分析器词元	标准分析器词元	空白分析器令牌
`White Lion`	`white`, `lion`	`white`, `lion`	`White`, `Lion`
`The Lion King`	`the`, `lion` , `king`	`the`, `lion` , `king`	`The`, `Lion` , `King`
`The Lion King 1 1/2`	`the`, `lion` , `king`	`the`, `lion` , `king` , `1` , `1` , `2`	`The`, `Lion` , `King` , `1` , `1/2`
`Lion's Den`	`lion`, `s` , `den`	`lion's`, `den`	`Lion's`, `Den`

MongoDB Search 在结果中返回文档Lion's Den，因为 simple分析器为 lion 创建了一个单独的词元，该词元与查询术语lion 匹配。相比之下，如果使用标准分析器或空格分析器对字段索引， MongoDB Search 将在查询结果中返回一些文档，但不会返回 Lion's Den，因为这些分析器会创建词元 lion's 和 Lion's分别创建，但不为 lion 创建令牌。

后退

标准分析器

来年

Whitespace

1	db.movies.createSearchIndex(
2	"default",
3	{
4	"mappings": {
5	"fields": {
6	"title": {
7	"type": "string",
8	"analyzer": "lucene.simple"
9	}
10	}
11	}
12	}
13	)

1	db.movies.aggregate([
2	{
3	"$search": {
4	"text": {
5	"query": "lion",
6	"path": "title"
7	}
8	}
9	},
10	{
11	"$limit": 5
12	},
13	{
14	"$project": {
15	"_id": 0,
16	"title": 1
17	}
18	}
19	])