Session: How to Use MoreLikeThis
MoreLikeThis is available through query extension methods and will return similar documents according to the provided criteria and options.
Syntax
IRavenQueryable<T> MoreLikeThis<T>(MoreLikeThisBase moreLikeThis);
IRavenQueryable<T> MoreLikeThis<T>(Action<IMoreLikeThisBuilder<T>> builder);
| Parameters |
|
|
| moreLikeThis |
MoreLikeThisBase |
Defines the type of MoreLikeThis that should be executed |
| builder |
Action<IMoreLikeThisFactory<T>> |
Builder with fluent API that constructs the MoreLikeThisBase instance |
Builder
IMoreLikeThisOperations<T> UsingAnyDocument();
IMoreLikeThisOperations<T> UsingDocument(string documentJson);
IMoreLikeThisOperations<T> UsingDocument(Expression<Func<T, bool>> predicate);
IMoreLikeThisOperations<T> WithOptions(MoreLikeThisOptions options);
| Parameters |
|
|
| documentJson |
string |
Inline JSON document that will be used as a base for operation |
| predicate |
Expression<Func<T, bool>> |
Filtering expression utilized to find a document that will be used as a base for operation |
| options |
MoreLikeThisOptions |
Non-default options that should be used for operation |
Options
public int? MinimumTermFrequency { get; set; } = 2;
public int? MaximumQueryTerms { get; set; } = 25;
public int? MaximumNumberOfTokensParsed { get; set; } = 5000;
public int? MinimumWordLength { get; set; } = 0;
public int? MaximumWordLength { get; set; } = 0;
public int? MinimumDocumentFrequency { get; set; } = 5;
public int? MaximumDocumentFrequency { get; set; } = int.MaxValue;
public int? MaximumDocumentFrequencyPercentage { get; set; }
public bool? Boost { get; set; } = false;
public float? BoostFactor { get; set; } = 1;
public string StopWordsDocumentId { get; set; }
public string[] Fields { get; set; }
| Options |
|
|
| MinimumTermFrequency |
int? |
Ignores terms with less than this frequency in the source doc |
| MaximumQueryTerms |
int? |
Returns a query with no more than this many terms |
| MaximumNumberOfTokensParsed |
int? |
The maximum number of tokens to parse in each example doc field that is not stored with TermVector support |
| MinimumWordLength |
int? |
Ignores words less than this length or, if 0, then this has no effect |
| MaximumWordLength |
int? |
Ignores words greater than this length or if 0 then this has no effect |
| MinimumDocumentFrequency |
int? |
Ignores words which do not occur in at least this many documents |
| MaximumDocumentFrequency |
int? |
Ignores words which occur in more than this many documents |
| MaximumDocumentFrequencyPercentage |
int? |
Ignores words which occur in more than this percentage of documents |
| Boost |
bool? |
Boost terms in query based on score |
| BoostFactor |
float? |
Boost factor when boosting based on score |
| StopWordsDocumentId |
string |
Document ID containing custom stop words |
| Fields |
string[] |
Fields to compare |
Example I
// Search for similar articles to 'articles/1'
// using 'Articles/MoreLikeThis' index and search only field 'Body'
List<Article> articles = session
.Query<Article>("Articles/MoreLikeThis")
.MoreLikeThis(builder => builder
.UsingDocument(x => x.Id == "articles/1")
.WithOptions(new MoreLikeThisOptions
{
Fields = new[] { "Body" }
}))
.ToList();
// Search for similar articles to 'articles/1'
// using 'Articles/MoreLikeThis' index and search only field 'Body'
List<Article> articles = await asyncSession
.Query<Article>("Articles/MoreLikeThis")
.MoreLikeThis(builder => builder
.UsingDocument(x => x.Id == "articles/1")
.WithOptions(new MoreLikeThisOptions
{
Fields = new[] { "Body" }
}))
.ToListAsync();
from index 'Articles/MoreLikeThis'
where morelikethis(id() = 'articles/1', '{ "Fields" : [ "Body" ] }')
Example II
// Search for similar articles to 'articles/1'
// using 'Articles/MoreLikeThis' index and search only field 'Body'
// where article category is 'IT'
List<Article> articles = session
.Query<Article>("Articles/MoreLikeThis")
.MoreLikeThis(builder => builder
.UsingDocument(x => x.Id == "articles/1")
.WithOptions(new MoreLikeThisOptions
{
Fields = new[] { "Body" }
}))
.Where(x => x.Category == "IT")
.ToList();
// Search for similar articles to 'articles/1'
// using 'Articles/MoreLikeThis' index and search only field 'Body'
// where article category is 'IT'
List<Article> articles = await asyncSession
.Query<Article>("Articles/MoreLikeThis")
.MoreLikeThis(builder => builder
.UsingDocument(x => x.Id == "articles/1")
.WithOptions(new MoreLikeThisOptions
{
Fields = new[] { "Body" }
}))
.Where(x => x.Category == "IT")
.ToListAsync();
from index 'Articles/MoreLikeThis'
where morelikethis(id() = 'articles/1', '{ "Fields" : [ "Body" ] }') and Category == 'IT'
Do not forget to add the following using statement which contains necessary extensions:
using Raven.Client.Documents;
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