Session: Querying: How to Work with Suggestions

The Suggestion feature is available through query extension methods. It gives you the ability to find word similarities using string distance algorithms.

Syntax

// This dynamic query on the 'Products' collection has NO resulting documents
List<Product> products = session
  .Query<Product>()
  .Where(x => x.Name == "chaig")
  .ToList();

Parameters
suggestion	SuggestionBase	Defines the type of suggestion that should be executed
builder	Action<ISuggestionBuilder<T>>	Builder with a fluent API that constructs a SuggestionBase instance

Builder

// Query for suggested terms for single term:
// ==========================================

Dictionary<string, SuggestionResult> suggestions = session
   // Make a dynamic query on collection 'Products'
  .Query<Product>()
   // Call 'SuggestUsing'
  .SuggestUsing(builder => builder
       // Request to get terms from field 'Name' that are similar to 'chaig' 
      .ByField(x => x.Name, "chaig"))
  .Execute();

Parameters
fieldName	string	Points to the index field that should be used for operation
path	Expression<Func<T, object>>	Points to the index field that should be used for operation
term	string	Term that will be used as a basis of the suggestions
terms	string[]	Terms that will be used as a basis of the suggestions
displayName	string	User defined friendly name for suggestion result. If null, field name will be used.
options	SuggestionOptions	Non-default options that should be used for operation

Options

// Query for suggested terms for multiple terms:
// =============================================

Dictionary<string, SuggestionResult> suggestions = session
   // Make a dynamic query on collection 'Products'
  .Query<Product>()
   // Call 'SuggestUsing'
  .SuggestUsing(builder => builder
       // Request to get terms from field 'Name' that are similar to 'chaig' OR 'tof' 
      .ByField(x => x.Name, new[] { "chaig", "tof" }))
  .Execute();

Options
PageSize	int	Maximum number of suggestions that will be returned
Distance	StringDistanceTypes	String distance algorithm to use (None, Levenshtein, JaroWinkler, NGram)
Accuracy	float?	Suggestion accuracy
SortMode	SuggestionSortMode	Indicates in what order the results should be returned (None, Popularity)

Multiple suggestions

You are able to ask for multiple suggestions using a single query.

// Query for suggested terms for single term:
// ==========================================

Dictionary<string, SuggestionResult> suggestions = await asyncSession
   // Make a dynamic query on collection 'Products'
  .Query<Product>()
   // Call 'SuggestUsing'
  .SuggestUsing(builder => builder
       // Request to get terms from field 'Name' that are similar to 'chaig'  
      .ByField(x => x.Name, "chaig"))
  .ExecuteAsync();

Example I

• Sync
• Async
• RQL

Dictionary<string, SuggestionResult> suggestions = session
  .Query<Employee, Employees_ByFullName>()
  .SuggestUsing(builder => builder
      .ByField("FullName", "johne")
      .WithOptions(new SuggestionOptions
      {
          Accuracy = 0.4f,
          PageSize = 5,
          Distance = StringDistanceTypes.JaroWinkler,
          SortMode = SuggestionSortMode.Popularity
      }))
  .Execute();

Dictionary<string, SuggestionResult> suggestions = await asyncSession
  .Query<Employee, Employees_ByFullName>()
  .SuggestUsing(builder => builder
      .ByField("FullName", "johne")
      .WithOptions(new SuggestionOptions
      {
          Accuracy = 0.4f,
          PageSize = 5,
          Distance = StringDistanceTypes.JaroWinkler,
          SortMode = SuggestionSortMode.Popularity
      }))
  .ExecuteAsync();

from index 'Employees/ByFullName' 
select suggest('FullName', 'johne', '{ "Accuracy" : 0.4, "PageSize" : 5, "Distance" : "JaroWinkler", "SortMode" : "Popularity" }')

Example II

• Sync
• Async
• RQL

Dictionary<string, SuggestionResult> suggestions = session
  .Query<Employee, Employees_ByFullName>()
  .SuggestUsing(new SuggestionWithTerm("FullName") { Term = "johne" })
  .Execute();

Dictionary<string, SuggestionResult> suggestions = await asyncSession
  .Query<Employee, Employees_ByFullName>()
  .SuggestUsing(new SuggestionWithTerm("FullName") { Term = "johne" })
  .ExecuteAsync();

from index 'Employees/ByFullName' 
select suggest('FullName', 'johne')

Example III

Looking for suggestions with dynamic query usage for multiple fields:

• Sync
• Async
• RQL

Dictionary<string, SuggestionResult> suggestions = session.Query<Employee>()
  .SuggestUsing(x => x
      .ByField(y => y.FirstName, "johne")
      .WithDisplayName("CustomLastName"))
  .AndSuggestUsing(x => x
      .ByField(y => y.LastName, "owen"))
  .Execute();

Dictionary<string, SuggestionResult> suggestions = await asyncSession.Query<Employee>()
  .SuggestUsing(x => x
      .ByField(y => y.FirstName, "johne")
      .WithDisplayName("CustomFirstName"))
  .AndSuggestUsing(x => x
      .ByField(y => y.LastName, "owen"))
  .ExecuteAsync();

from Employees 
select suggest('FirstName', 'johne') as CustomFirstName, suggest('LastName', 'owen')