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Hi, there are multiple issues that i encountered while working with building a SearchDefinition to run $search, let me know if i’m doing something wrong

  1. Can’t create equals on string SearchDefinition, for example
    Builders.Search.Equals(“field”,“value”) won’t compile because of the constraint on TField
    The type ‘string’ must be a non-nullable value type in order to use it as parameter ‘TField’.
    as far as i understood .Search.Text is a different command and needs a different index (string and not token)
  2. Working with GUIDs, i see that search index is able to index UUID fields, however when using .Search.Equals(“field”, someGuid) i receive InvalidCastException, i see that the internal function supports ObjectId however as far as i understood these 2 types are not exactly the same.

Thanks

2 Likes
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Hello!
It looks like you’re facing issues with SearchDefinition in $search. For string fields, use Builders.Search.Text instead of Equals, as Equals requires non-nullable value types. For GUIDs, ensure your index field type matches the type you’re querying. If you’re getting an InvalidCastException, it might be due to a type mismatch between UUID and ObjectId. Here’s a quick example:

C#

// Text search
var textSearch = Builders.Search.Text(“field”, “value”);

// GUID search
var guid = new Guid(“your-guid-here”);
var guidSearch = Builders.Search.Equals(“field”, guid);

Hope this helps!

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Hi Anne, .Search.Text is different than .Search.Equals it uses a different index which is not what i intend to use.
Regarding your guid example, that won’t work as i wrote it will throw InvalidcastException

3 Likes
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I am having this issue as well. In the Atlas search tester, I am able to pass in a string to match a tokenized index. But in C#, I am unable to call Equals as it rejects string. In this page: https://www.mongodb.com/docs/atlas/atlas-search/equals/ it says it accepts string if the index is token, which is what I have it set up as.

Changing to Text or Phrase does not give me the result I want that I get from Equals in the search tester

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I found a workaround. You can create a BsonDocument, like this:

public BsonDocument Equals(string field, string value, double? boost = null)
    {
        var equalsDef = new BsonDocument
        {
            {
                "equals",
                new BsonDocument { { "path", field }, { "value", value } }
            }
        };

        if (boost.HasValue)
        {
            equalsDef["equals"]["score"] = new BsonDocument
            {
                {
                    "boost",
                    new BsonDocument { { "value", boost } }
                }
            };
        }

        return equalsDef;
    }