Multi Analyzer

You can use the multi object in your index definition to specify alternate analyzers with which to also index the field. When you index a field with alternate analyzers in addition to the default analyzer, you can search the collection with either the default or the alternate analyzer. This page demonstrates how to specify alternate analyzers in your index definition using multi.

Multi Analyzer Limitations

The multi path option is available only to fields of type string.

Atlas Search does not support nesting multiple layers of multi objects.

Examples

The following examples demonstrate index definitions on the fields in the sample_mflix.movies collection. If you load the collection on your cluster, you can create the example indexes using the Visual Editor or the JSON Editor in the Atlas UI or using mongosh.

➤ Use the Select your language drop-down menu to set the interface for the example on this page.

Single Field Example

The following example index definition specifies an index on the title field using the standard analyzer. The index definition also specifies lucene.french analyzer as an alternate analyzer for the title field, with the name frenchAnalyzer.

Click Refine Your Index to configure your index.
In the Field Mappings section, click Add Field to open the Add Field Mapping window.
Select title from the Field Name dropdown.
Click the Data Type dropdown and select String if it isn't already selected.

Expand String Properties and make the following changes:

Index Analyzer	Select `lucene.standard` from the dropdown if it isn't already selected.
Search Analyzer	Select `lucene.standard` from the dropdown if it isn't already selected.
Index Options	Use the default `offsets`.
Store	Use the default `true`.
Ignore Above	Keep the default setting.
Norms	Use the default `include`.

Click Add Multi Field to configure another analyzer on the title field.
Enter frenchAnalyzer in the Multi Field Name field.

Make the following changes to the Multi Field Properties :

Index Analyzer	Select `lucene.french` from the dropdown if it isn't already selected.
Search Analyzer	Select `lucene.french` from the dropdown if it isn't already selected.
Index Options	Use the default `offsets`.
Store	Use the default `true`.
Ignore Above	Keep the default setting.
Norms	Use the default `include`.

Click Add.
Click Save Changes.
Click Create Search Index.

Replace the default index definition with the following index definition.

1 {
2   "mappings": {
3     "dynamic": false,
4     "fields": {
5       "title": {
6         "type": "string",
7         "analyzer": "lucene.standard",
8         "multi": {
9           "frenchAnalyzer": {
10             "type": "string",
11             "analyzer": "lucene.french"
12           }
13         }
14       }
15     }
16   }
17 }

Click Next.
Click Create Search Index.

1 db.movies.createSearchIndex(
2   "default",
3     {
4       "mappings": {
5         "dynamic": false,
6         "fields": {
7           "title": {
8             "type": "string",
9             "analyzer": "lucene.standard",
10             "multi": {
11               "frenchAnalyzer": {
12                 "type": "string",
13                 "analyzer": "lucene.french"
14               }
15           }
16         }
17       }
18     }
19   }
20 )

The following query uses the alternate analyzer, named frenchAnalyzer, to search for the string liberte.

Click the Query button for your index.
Click Edit Query to edit the query.
Click on the query bar and select the database and collection.

Replace the default query with the following and click Find:

[
  {
    "$search": {
      "text": {
        "query": "liberte",
        "path": { "value": "title", "multi": "frenchAnalyzer" }
      }
    }
  }
]

SCORE: 4.9305267333984375  _id:  "573a1392f29313caabcd9950"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   fullplot: "A famous left-wing satirical comedy about two ex-convicts, one of whom…"
   genres: Array (2)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-08-21 00:02:36.330000000"
   num_mflix_comments: 1
   plot: "A famous left-wing satirical comedy about two ex-convicts, one of whom…"
   poster: "https://m.media-amazon.com/images/M/MV5BODg0ODAzNTItM2M4ZC00NGYxLWIzMm…"
   rated: "APPROVED"
   released: 1931-12-31T00:00:00.000+00:00
   runtime: 97
   title: "è Nous la Libertè"
   tomatoes: Object
   type: "movie"
   writers: Array (1)
   year: 1931

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

[ { title: 'è Nous la Libertè', year: 1931 } ]

The document in the results is a match because the frenchAnalyzer reduced both the indexed string è Nous la Libertè and query term liberte to the base word libert. Atlas Search won't return this document for a search with the standard analyzer because it doesn't remove diacritics. Each analyzer generates the following tokens (searchable terms) for the index and query:

Analyzer	Index Tokens	Query Tokens
Standard Analyzer	`è`, `nous`, `la`, `libertè`	`libertè`
French Analyzer	`è`, `libert`	`libert`

Multiple Fields Example

The following example index definition specifies an index on the title and plot fields using the standard analyzer. The index definition also specifies lucene.french as an alternate analyzer for the title and the plot fields.

Click Refine Your Index to configure your index.
In the Field Mappings section, click Add Field to open the Add Field Mapping window.
Select title from the Field Name dropdown.
Click the Data Type dropdown and select String if it isn't already selected.

Expand String Properties and make the following changes:

Index Analyzer	Select `lucene.standard` from the dropdown if it isn't already selected.
Search Analyzer	Select `lucene.standard` from the dropdown if it isn't already selected.
Index Options	Use the default `offsets`.
Store	Use the default `true`.
Ignore Above	Keep the default setting.
Norms	Use the default `include`.

Click Add Multi Field to configure another analyzer on the title field.
Enter frenchAnalyzer in the Multi Field Name field.

Make the following changes to the Multi Field Properties :

Index Analyzer	Select `lucene.french` from the dropdown if it isn't already selected.
Search Analyzer	Select `lucene.french` from the dropdown if it isn't already selected.
Index Options	Use the default `offsets`.
Store	Use the default `true`.
Ignore Above	Keep the default setting.
Norms	Use the default `include`.

Click Add.
Click Add Field Mapping to open the Add Field Mapping window.
Select plot from the Field Name dropdown.
Repeat steps 4 to 9.
Click Save Changes.
Click Create Search Index.

Replace the default index definition with the following index definition.

1 {
2   "mappings": {
3     "dynamic": false,
4     "fields": {
5       "title": {
6         "type": "string",
7         "analyzer": "lucene.standard",
8         "multi": {
9           "frenchAnalyzer": {
10             "type": "string",
11             "analyzer": "lucene.french"
12           }
13         }
14       },
15       "plot": {
16         "type": "string",
17         "analyzer": "lucene.standard",
18         "multi": {
19           "frenchAnalyzer": {
20             "type": "string",
21             "analyzer": "lucene.french"
22           }
23         }
24       }
25     }
26   }
27 }

Click Next.
Click Create Search Index.

1 db.movies.createSearchIndex(
2   "default",
3     {
4       "mappings": {
5         "dynamic": false,
6         "fields": {
7           "title": {
8             "type": "string",
9             "analyzer": "lucene.standard",
10             "multi": {
11               "frenchAnalyzer": {
12                 "type": "string",
13                 "analyzer": "lucene.french"
14               }
15             }
16           },
17           "plot": {
18             "type": "string",
19             "analyzer": "lucene.standard",
20             "multi": {
21               "frenchAnalyzer": {
22                 "type": "string",
23                 "analyzer": "lucene.french"
24               }
25             }
26           }
27         }
28       }
29     }
30 )

The following query searches for matches for the string revolution in the title and the plot fields by using the alternate analyzer named frenchAnalyzer.

Click the Query button for your index.
Click Edit Query to edit the query.
Click on the query bar and select the database and collection.

Replace the default query with the following and click Find:

[
  {
    "$search": {
      "text": {
        "query": "revolution",
          "path": [
            "title", "plot",
            { "value": "title", "multi": "frenchAnalyzer" },
            {  "value": "plot", "multi": "frenchAnalyzer" }
         ]
      }
    }
  }
]

SCORE: 14.07243537902832   _id:  "573a13dbf29313caabdaf845"
   awards: Object
   cast: Array (4)
   countries: Array (11)
   directors: Array (1)
   fullplot: "REVOLUTION is a film about changing the world, going for it, taking a …"
   genres: Array (3)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-07-09 11:14:18.300000000"
   metacritic: 53
   num_mflix_comments: 0
   plot: "REVOLUTION is a film about changing the world, going for it, taking a …"
   poster: "https://m.media-amazon.com/images/M/MV5BMTc1NDIxNjc0N15BMl5BanBnXkFtZT…"
   rated: "PG"
   released: 2015-04-22T00:00:00.000+00:00
   runtime: 85
   title: "Revolution"
   tomatoes: Object
   type: "movie"
   writers: Array (1)
   year: 2012
SCORE: 13.935744285583496   _id:  "573a1398f29313caabce9ae2"
   awards: Object
   cast: Array (4)
   countries: Array (2)
   directors: Array (1)
   fullplot: "New York trapper Tom Dobb becomes an unwilling participant in the Amer…"
   genres: Array (3)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-08-14 00:46:28.990000000"
   num_mflix_comments: 1
   plot: "New York trapper Tom Dobb becomes an unwilling participant in the Amer…"
   poster: "https://m.media-amazon.com/images/M/MV5BZmZhMmEyNjktZTgxZC00NzQyLTkyZD…"
   rated: "PG-13"
   released: 1985-12-25T00:00:00.000+00:00
   runtime: 126
   title: "Revolution"
   type: "movie"
   writers: Array (1)
   year: 1985
SCORE: 11.623137474060059   _id:  "573a13f5f29313caabde37d4"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   fullplot: "Together with five Soviet avant-garde artists, hero of the Russian rev…"
   genres: Array (1)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-09-15 03:33:53.177000000"
   num_mflix_comments: 1
   plot: "Together with five Soviet avant-garde artists, hero of the Russian rev…"
   released: 2014-11-18T00:00:00.000+00:00
   runtime: 113
   title: "Angels of Revolution"
   type: "movie"
   writers: Array (3)
   year: 2014
SCORE: 11.210482597351074   _id:  "573a1396f29313caabce4248"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   fullplot: "An account of the adventures of two sets of identical twins, badly scr…"
   genres: Array (2)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-09-05 00:50:08.277000000"
   num_mflix_comments: 0
   plot: "Two mismatched sets of identical twins - one aristocrat, one peasant -…"
   poster: "https://m.media-amazon.com/images/M/MV5BODM2MzE3NmMtNmE2ZS00OGI2LWI5NT…"
   rated: "M"
   released: 1970-08-14T00:00:00.000+00:00
   runtime: 90
   title: "Start the Revolution Without Me"
   tomatoes: Object
   type: "movie"
   writers: Array (2)
   year: 1970
SCORE: 8.332647323608398   _id:  "573a1398f29313caabceba10"
   awards: Object
   cast: Array (4)
   countries: Array (5)
   directors: Array (2)
   fullplot: "A history of the French Revolution from the decision of the king to co…"
   genres: Array (3)
   imdb: Object
   languages: Array (2)
   lastupdated: "2015-09-05 00:30:36.643000000"
   num_mflix_comments: 0
   plot: "A history of the French Revolution from the decision of the king to co…"
   released: 1989-10-25T00:00:00.000+00:00
   runtime: 360
   title: "La rèvolution franèaise"
   tomatoes: Object
   type: "movie"
   writers: Array (5)
   year: 1989
SCORE: 7.699893474578857   _id:  "573a13a4f29313caabd10215"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   genres: Array (1)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-09-10 17:19:25.853000000"
   metacritic: 63
   num_mflix_comments: 0
   poster: "https://m.media-amazon.com/images/M/MV5BMTkxOTUzNjg0Ml5BMl5BanBnXkFtZT…"
   released: 2001-04-22T00:00:00.000+00:00
   runtime: 90
   title: "Revolution #9"
   tomatoes: Object
   type: "movie"
   writers: Array (1)
   year: 2001
SCORE: 6.8415961265563965   _id:  "573a13a0f29313caabd05edb"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   fullplot: "Friendship and betrayal between two poets during the French Revolution…"
   genres: Array (2)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-04-17 01:56:58.940000000"
   metacritic: 60
   num_mflix_comments: 0
   plot: "Friendship and betrayal between two poets during the French Revolution…"
   poster: "https://m.media-amazon.com/images/M/MV5BMTQ0Nzc0OTkwM15BMl5BanBnXkFtZT…"
   rated: "PG-13"
   released: 2001-04-18T00:00:00.000+00:00
   runtime: 124
   title: "Pandaemonium"
   tomatoes: Object
   type: "movie"
   writers: Array (1)
   year: 2000
SCORE: 6.7074995040893555   _id:  "573a1397f29313caabce8972"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   fullplot: "Set ten years after the most peaceful revolution in United States hist…"
   genres: Array (3)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-09-10 17:14:53.427000000"
   num_mflix_comments: 1
   plot: "Set ten years after the most peaceful revolution in United States hist…"
   poster: "https://m.media-amazon.com/images/M/MV5BYTE5MGNhN2QtMTNhYy00MDQ1LTgzOT…"
   released: 1983-11-03T00:00:00.000+00:00
   runtime: 80
   title: "Born in Flames"
   tomatoes: Object
   type: "movie"
   writers: Array (2)
   year: 1983
SCORE: 6.615457057952881   _id:  "573a1395f29313caabce1c90"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   fullplot: "The study of a youth on the edge of adulthood and his aunt, ten years …"
   genres: Array (2)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-08-21 00:16:07.580000000"
   num_mflix_comments: 0
   plot: "The study of a youth on the edge of adulthood and his aunt, ten years …"
   poster: "https://m.media-amazon.com/images/M/MV5BMmJjOGRjNWMtOGE5Ni00YzYwLThkM2…"
   released: 1964-05-12T00:00:00.000+00:00
   runtime: 105
   title: "Before the Revolution"
   tomatoes: Object
   type: "movie"
   writers: Array (2)
   year: 1964
SCORE: 6.615457057952881   _id:  "573a13cef29313caabd86ecc"
   awards: Object
   cast: Array (1)
   countries: Array (1)
   directors: Array (1)
   fullplot: "Through intimate interviews, provocative art, and rare, historical fil…"
   genres: Array (1)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-04-02 00:54:39.997000000"
   metacritic: 70
   num_mflix_comments: 1
   plot: "Through intimate interviews, provocative art, and rare, historical fil…"
   poster: "https://m.media-amazon.com/images/M/MV5BMjE1MDU1MDA2Nl5BMl5BanBnXkFtZT…"
   released: 2011-06-01T00:00:00.000+00:00
   runtime: 83
   title: "!Women Art Revolution"
   tomatoes: Object
   type: "movie"
   year: 2010

1 db.movies.aggregate([
2   {
3     "$search": {
4       "text": {
5         "query": "revolution",
6         "path": ["title", "plot",
7           { "value": "title", "multi": "frenchAnalyzer" },
8           {  "value": "plot", "multi": "frenchAnalyzer" }
9         ]
10       }
11     }
12   },
13   {
14     "$limit": 5
15   },
16   {
17     "$project": {
18       "title": 1,
19       "plot": 1,
20       "year": 1,
21       "_id": 0
22     }
23   }
24 ])

[
  {
    year: 2012,
    plot: 'REVOLUTION is a film about changing the world, going for it, taking a stand, and fighting for something. A true-life adventure following Director, Rob Stewart (SHARKWATER) over four years ...',
    title: 'Revolution'
  },
  {
    plot: 'New York trapper Tom Dobb becomes an unwilling participant in the American Revolution after his son Ned is drafted into the Army by the villainous Sergeant Major Peasy. Tom attempts to find...',
    title: 'Revolution',
   year: 1985
  },
  {
    plot: "Together with five Soviet avant-garde artists, hero of the Russian revolution Polina Schneider travels to Siberia to 'civilize' the native Khanty and Nenets tribes, for whom interaction ...",
    title: 'Angels of Revolution',
    year: 2014
  },
  {
    plot: 'Two mismatched sets of identical twins - one aristocrat, one peasant - mistakenly exchange identities on the eve of the French Revolution.',
    title: 'Start the Revolution Without Me',
    year: 1970
  },
  {
    plot: "A history of the French Revolution from the decision of the king to convene the Etats-Generaux in 1789 in order to deal with France's debt problem. The first part of the movie tells the ...",
    title: 'La rèvolution franèaise',
    year: 1989
  }
]

The documents in the results contain the query term in both the title and the plot fields. Each analyzer creates the following tokens (searchable terms) for the title field for each document in the results:

Year	Analyzer	Index Tokens	Query Tokens
2012	Standard Analyzer French Analyzer	`revolution` `revolution`	`revolution` `revolution`
1985	Standard Analyzer French Analyzer	`revolution` `revolution`	`revolution` `revolution`
2014	Standard Analyzer French Analyzer	`angels`, `of`, `revolution` `angels`, `of`, `revolution`	`revolution` `revolution`
1970	Standard Analyzer French Analyzer	`start`, `the`, `revolution`, `without`, `me` `start`, `the`, `revolution`, `without`	`revolution` `revolution`
1989	Standard Analyzer French Analyzer	`la`, `rèvolution`, `franèaise` `revolution`, `franeais`	`revolution` `revolution`

For the fifth document in the results, the frenchAnalyzer removed the diacritics in the title field to match the document to the query term.

Back

Language

Custom

1	{
2	"mappings": {
3	"dynamic": false,
4	"fields": {
5	"title": {
6	"type": "string",
7	"analyzer": "lucene.standard",
8	"multi": {
9	"frenchAnalyzer": {
10	"type": "string",
11	"analyzer": "lucene.french"
12	}
13	}
14	}
15	}
16	}
17	}

1	db.movies.createSearchIndex(
2	"default",
3	{
4	"mappings": {
5	"dynamic": false,
6	"fields": {
7	"title": {
8	"type": "string",
9	"analyzer": "lucene.standard",
10	"multi": {
11	"frenchAnalyzer": {
12	"type": "string",
13	"analyzer": "lucene.french"
14	}
15	}
16	}
17	}
18	}
19	}
20	)

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