Boost Search Results
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When querying with some filtering conditions,
a basic score is calculated for each document in the results by the underlying engine. -
Providing a boost value to some fields allows you to prioritize the resulting documents.
The boost value is integrated with the basic score, making the document rank higher. -
Boosting can be achieved in the following ways:
-
At query time:
Apply a boost factor to searched terms at query time - as described in this article. -
Via index definition:
Apply a boost factor in your index definition - see this boosting indexing article.
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The automatic ordering of the results by the score is configurable.
Learn more here: automatic score-based ordering -
The calculated score details of the results can be retrieved if needed.
Learn more here: get resulting score -
In this article:
Boost results - when making a full-text search
When making a full-text search with the Search() method then boosting can be applied
to both Query and DocumentQuery.
- Query
- Query_async
- DocumentQuery
- RQL
List<Employee> employees = session
// Make a dynamic full-text search Query on 'Employees' collection
.Query<Employee>()
// This search predicate will use the default boost value of 1
.Search(x => x.Notes, "English")
// * Pass the boost value using the 'boost' parameter
// * This search predicate will use a boost value of 10
.Search(x => x.Notes, "Italian", boost: 10)
.ToList();
// * Results will contain all Employee documents that have
// EITHER 'English' OR 'Italian' in their 'Notes' field (case-insensitive).
//
// * Matching documents that contain 'Italian' will get a HIGHER score
// than those that contain 'English'.
//
// * Unless configured otherwise, the resulting documents will be ordered by their score.
List<Employee> employees = await asyncSession
// Make a dynamic full-text search Query on 'Employees' collection
.Query<Employee>()
// This search predicate will use the default boost value of 1
.Search(x => x.Notes, "English")
// * Pass the boost value using the 'boost' parameter
// * This search predicate will use a boost value of 10
.Search(x => x.Notes, "Italian", boost: 10)
.ToListAsync();
// * Results will contain all Employee documents that have
// EITHER 'English' OR 'Italian' in their 'Notes' field (case-insensitive).
//
// * Matching documents that contain 'Italian' will get a HIGHER score
// than those that contain 'English'.
//
// * Unless configured otherwise, the resulting documents will be ordered by their score.
List<Employee> employees = session.Advanced
// Make a dynamic full-text search DocumentQuery on 'Employees' collection
.DocumentQuery<Employee>()
// This search predicate will use the default boost value of 1
.Search(x => x.Notes, "English")
// This search predicate will use a boost value of 10
.Search(x => x.Notes, "Italian")
// Call 'Boost' to set the boost value of the previous 'Search' call
.Boost(10)
.ToList();
// * Results will contain all Employee documents that have
// EITHER 'English' OR 'Italian' in their 'Notes' field (case-insensitive).
//
// * Matching documents that contain 'Italian' will get a HIGHER score
// than those that contain 'English'.
//
// * Unless configured otherwise, the resulting documents will be ordered by their score.
from "Employees" where
search(Notes, "English") or boost(search(Notes, "Italian"), 10)
Boost results - when querying with where clause
When querying with Where clauses (using an OR condition in between) then boosting can be applied
only with DocumentQuery.
- DocumentQuery
- DocumentQuery_async
- RQL
List<Company> companies = session.Advanced
// Make a dynamic DocumentQuery on 'Companies' collection
.DocumentQuery<Company>()
// Define a 'Where' condition
.WhereStartsWith(x => x.Name, "O")
// Call 'Boost' to set the boost value of the previous 'Where' predicate
.Boost(10)
// Call 'OrElse' so that OR operator will be used between statements
.OrElse()
.WhereStartsWith(x => x.Name, "P")
.Boost(50)
.OrElse()
.WhereEndsWith(x => x.Name, "OP")
.Boost(90)
.ToList();
// * Results will contain all Company documents that either
// (start-with 'O') OR (start-with 'P') OR (end-with 'OP') in their 'Name' field (case-insensitive).
//
// * Matching documents that end-with 'OP' will get the HIGHEST scores.
// Matching documents that start-with 'O' will get the LOWEST scores.
//
// * Unless configured otherwise, the resulting documents will be ordered by their score.
List<Company> companies = await asyncSession.Advanced
// Make a dynamic DocumentQuery on 'Companies' collection
.AsyncDocumentQuery<Company>()
// Define a 'Where' condition
.WhereStartsWith(x => x.Name, "O")
// Call 'Boost' to set the boost value of the previous 'Where' predicate
.Boost(10)
// Call 'OrElse' so that OR operator will be used between statements
.OrElse()
.WhereStartsWith(x => x.Name, "P")
.Boost(50)
.OrElse()
.WhereEndsWith(x => x.Name, "OP")
.Boost(90)
.ToListAsync();
// * Results will contain all Company documents that either
// (start-with 'O') OR (start-with 'P') OR (end-with 'OP') in their 'Name' field (case-insensitive).
//
// * Matching documents that end-with 'OP' will get the HIGHEST scores.
// Matching documents that start-with 'O' will get the LOWEST scores.
//
// * Unless configured otherwise, the resulting documents will be ordered by their score.
from "Companies" where
boost(startsWith(Name, "O"), 10) or
boost(startsWith(Name, "P"), 50) or
boost(endsWith(Name, "OP"), 90)
Boost a WhereExists() condition with Corax
In RavenDB 7.2.6 and later, when using the Corax search engine, a boosted WhereExists() condition (exists() in RQL)
contributes 1 multiplied by the query boost, rather than a relevance score calculated from the field's values.
For example, .WhereExists(x => x.Fax).Boost(3) (boost(exists(Fax), 3) in RQL) contributes 3
once per matching document, before any index-entry boost is applied.
The WhereStartsWith() and WhereEndsWith() conditions in the example above use relevance-based scoring.
Learn more in Corax: Scoring.