Text Search¶
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Overview¶
MongoDB supports query operations that perform a text search of string content. To perform text search, MongoDB uses a text index and the $text operator.
Example¶
This example demonstrates how to build a text index and use it to find coffee shops, given only text fields.
Create a collection stores with the following documents:
db.stores.insert(
[
{ _id: 1, name: "Java Hut", description: "Coffee and cakes" },
{ _id: 2, name: "Burger Buns", description: "Gourmet hamburgers" },
{ _id: 3, name: "Coffee Shop", description: "Just coffee" },
{ _id: 4, name: "Clothes Clothes Clothes", description: "Discount clothing" },
{ _id: 5, name: "Java Shopping", description: "Indonesian goods" }
]
)
Text Index¶
MongoDB provides text indexes to support text search queries on string content. text indexes can include any field whose value is a string or an array of string elements.
To perform text search queries, you must have a text index on your collection. A collection can only have one text search index, but that index can cover multiple fields.
For example you can run the following in a mongo shell to allow text search over the name and description fields:
db.stores.createIndex( { name: "text", description: "text" } )
$text Operator¶
Use the $text query operator to perform text searches on a collection with a text index.
$text will tokenize the search string using whitespace and most punctuation as delimiters, and perform a logical OR of all such tokens in the search string.
For example, you could use the following query to find all stores containing any terms from the list “coffee”, “shop”, and “java”:
db.stores.find( { $text: { $search: "java coffee shop" } } )
Exact Phrase¶
You can also search for exact phrases by wrapping them in double-quotes. For example, the following will find all documents containing “java” or “coffee shop”:
db.stores.find( { $text: { $search: "java \"coffee shop\"" } } )
Term Exclusion¶
To exclude a word, you can prepend a “-” character. For example, to find all stores containing “java” or “shop” but not “coffee”, use the following:
db.stores.find( { $text: { $search: "java shop -coffee" } } )
Sorting¶
MongoDB will return its results in unsorted order by default. However, text search queries will compute a relevance score for each document that specifies how well a document matches the query.
To sort the results in order of relevance score, you must explicitly project the $meta textScore field and sort on it:
db.stores.find(
{ $text: { $search: "java coffee shop" } },
{ score: { $meta: "textScore" } }
).sort( { score: { $meta: "textScore" } } )
Text search is also available in the aggregation pipeline.
Language Support¶
MongoDB supports text search for various languages. See Text Search Languages for a list of supported languages.