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Review Atlas Search Index Syntax

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  • Syntax
  • Options

Atlas Search can index data in different ways. When you define an Atlas Search index, you can specify a particular analyzer or multiple analyzers to index certain fields. To learn more, see Process Data with Analyzers. You can also index certain fields and omit others, or you can dynamically index all the fields in a collection. To learn more, see Define Field Mappings. You can define Atlas Search indexes through the Atlas UI, Atlas Search API, Atlas CLI, mongosh, or Drivers.

This page describes the JSON syntax and fields for an Atlas Search index.

Important

If you use the $out aggregation stage to modify a collection with an Atlas Search index, you must delete and re-create the search index. If possible, consider using $merge instead of $out.

Syntax

1{ 
2  "mappings": { 
3    "dynamic": <boolean>, 
4    "fields": { <field-definition> } 
5  }
6}
7  
1{  
2  "analyzer": "<analyzer-for-index>", 
3  "searchAnalyzer": "<analyzer-for-query>", 
4  "mappings": { 
5    "dynamic": <boolean>, 
6    "fields": { <field-definition> } 
7  }, 
8  "analyzers": [ <custom-analyzer> ],
9  "storedSource": <boolean> | {
10    <stored-source-definition>
11  },
12  "synonyms": [
13    {
14      "name": "<synonym-mapping-name>",
15      "source": {
16        "collection": "<source-collection-name>"
17      },
18      "analyzer": "<synonym-mapping-analyzer>"
19    }
20  ] 
21}
22

Options

Field
Type
Necessity
Description
analyzer
string
Optional
Specifies the analyzer to apply to string fields when indexing. If you set this only at the top and do not specify an analyzer for the fields in the index definition, Atlas Search applies this analyzer to all the fields. To use a different analyzer for each field, you must specify a different analyzer for the field. If omitted, defaults to Standard Analyzer.
analyzers
Optional
Specifies the Custom Analyzers to use in this index.
mappings
Required
Specifies how to index fields at different paths for this index.
mappings.dynamic
boolean
Optional

Enables or disables dynamic mapping of fields for this index.

If set to true, Atlas Search recursively indexes all dynamically indexable fields.

If set to false, you must specify individual fields to index using mappings.fields.

If omitted, defaults to false.

Important

Atlas Search dynamically indexes all fields in a document using the default settings for the detected data type. Atlas Search also dynamically indexes all nested documents under the document, unless you explicitly override by setting dynamic to false.

To learn more, see index configuration example.

mappings.fields
document
Conditional

Required only if dynamic mapping is disabled.

Specifies the fields that you would like to index. To learn more, see Define Field Mappings.

Note

You can't index fields that contain the dollar ($) sign at the start of the field name.

searchAnalyzer
string
Optional
Specifies the analyzer to apply to query text before searching with it. If omitted, defaults to the analyzer that you specify for the analyzer option. If you omit both the searchAnalyzer and the analyzer options, defaults to the Standard Analyzer.
storedSource
Optional

Specifies fields in the documents to store for query-time look-ups using the returnedStoredSource option. You can store fields of all Data Types on Atlas Search. Value can be one of the following:

  • true, to store all fields

  • false, to not store any fields

  • Object that specifies the fields to include or exclude from storage

If omitted, defaults to false. To learn more about the syntax and fields, see Define Stored Source Fields in Your Atlas Search Index.

Note

storedSource is only available on Atlas clusters running one of the following versions:

  • MongoDB 5.0.6+

  • MongoDB 6.0+

  • MongoDB 7.0+

synonyms
Optional

Synonym mappings to use in your index. To learn more, see Define Synonym Mappings in Your Atlas Search Index.

Note

An index definition can have only one synonym mapping.

Back

4: Configure Synonym Mappings

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