simple

For the complete MongoDB documentation index, see www.mongodb.com/docs/llms.txt

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Simple Analyzer

The simple analyzer divides text into searchable terms (tokens) wherever it finds a non-letter character, such as whitespace, punctuation, or one or more digits. It converts all text to lowercase.

If you select Refine Your Index, the Atlas UI displays a section titled View text analysis of your selected index configuration within the Index Configurations section. If you expand this section, the Atlas UI displays the index and search tokens that the simple analyzer generates for each sample string. You can see the tokens that the simple analyzer creates for a built-in sample document and query string when you create or edit an index in the Atlas UI Visual Editor.

Important:

MongoDB Search won't index string fields where analyzer tokens exceed 32766 bytes in size. If using the keyword analyzer, string fields which exceed 32766 bytes will not be indexed.

Example

The following example index definition specifies an index on the title field in the [sample_mflix.movies](https://www.mongodb.com/docs/manual/sample-data/sample-mflix.md#std-label-sample-mflix collection using the simple analyzer. To follow along with this example, [load the sample data](https://www.mongodb.com/docs/atlas/import/load-sample-data.md#std-label-sample-data on your cluster and either use [mongosh](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh or navigate to the Create a Search Index page in the Atlas UI following the steps in the [Create a MongoDB Search Index](https://www.mongodb.com/docs/search/tutorial.md#std-label-create-fts-index tutorial.

Then, using the movies collection as your data source, follow the example procedure to create an index from [mongosh](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh or the Atlas UI Visual Editor or JSON editor.

Visual Editor

  1. Click Refine Your Index to configure your index.

  2. In the Index Configurations section, toggle Dynamic Mapping to off.

  3. In the Field Mappings section, click Add Field to open the Add Field Mapping window.

  4. Click Customized Configuration.

  5. Select title from the Field Name dropdown.

  6. Click the Data Type dropdown and select String if it isn't already selected.

  7. Expand String Properties and make the following changes:

Index Analyzer Select lucene.simple from the dropdown.
Search Analyzer Select lucene.simple from the dropdown.
Index Options Use the default offsets.
Store Use the default true.
Ignore Above Keep the default setting.
Norms Use the default include.

  1. Click Add.

  2. Click Save Changes.

  3. Click Create Search Index.

db.movies.createSearchIndex(
  "default",
    {
      "mappings": {
        "fields": {
          "title": {
            "type": "string",
            "analyzer": "lucene.simple"
          }
        }
      }
    }
)

The following query searches for the term lion in the title field and limits the output to five results.

  1. Click the Query button for your index.

  2. Click Edit Query to edit the query.

  3. Click on the query bar and select the database and collection.

  4. Replace the default query with the following and click Find:

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

Output:

```js 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 ```

db.movies.aggregate([
  {
    "$search": {
      "text": {
         "query": "lion",
         "path": "title"
      }
    }
  },
  {
    "$limit": 5
  },
  {
    "$project": {
      "_id": 0,
      "title": 1
    }
  }
])

Output:

[
  { 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 returns these documents by doing the following for the text in the title field using the lucene.simple analyzer:

  • Convert text to lowercase.

  • Create separate tokens by dividing text wherever there is a non-letter character.

The following table shows the tokens that MongoDB Search creates for each document in the results using the [Simple Analyzer](https://www.mongodb.com/docs/search/indexes/analyzers/simple.md#std-label-ref-simple-analyzer. For comparison, the table also shows tokens from the [Standard Analyzer](https://www.mongodb.com/docs/search/indexes/analyzers/standard.md#std-label-ref-standard-analyzer and [Whitespace Analyzer:](https://www.mongodb.com/docs/search/indexes/analyzers/whitespace.md#std-label-ref-whitespace-analyzer

Title Simple Analyzer Tokens Standard Analyzer Tokens Whitespace Analyzer Tokens
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 returns document Lion's Den in the results because the simple analyzer creates a separate token for lion, which matches the query term lion. By contrast, if you index the field using the Standard Analyzer.