Mongo Atlas search index for both partial matches and case-insensitive queries-CodePudding

Using Mongo Atlas Search I have already achieved the setup that allows for searching using partially matched queries:

Created this index (without dynamic field mapping), called "search_organizations_name":

{
   "name": {
       "type": "string",
       "analyzer": "lucene.keyword",
       "searchAnalyzer": "lucene.keyword"
   }
}

And leveraged it in code like this (simplified and anonimised):

func (r *Repo) Search(ctx context.Context, query string) ([]Organization, error) {
    querySplit := strings.Split(query, " ")

    // Adding fuzzing.
    for i := range querySplit {
        querySplit[i] = fmt.Sprintf("*%s*", querySplit[i]) 
    }

    // Define pipeline stages.
    searchStage := bson.D{
        {"$search", bson.D{
            {"index, "search_organizations_name"},
            {"wildcard", bson.D{
                {"path", "name"},
                {"query", querySplit},
            }},
        }},
    }

    // Run pipeline.
    cursor, err := r.organizationsCollection().
        Aggregate(ctx, mongo.Pipeline{searchStage})
    if err != nil {// handling err}

    var orgs []Organization
    if err = cursor.All(ctx, &orgs); err != nil {
        return nil, errors.Wrap(err, "parsing organizations to return")
    }

    return orgs, nil
}

This works fine, but it is case sensitive search, which is not ideal. Researching the topic resulted in the following finds:

found suggestion to leverage collation, but search indices don't seem to have it as per docs
found suggestion to use lucene.standard as it's case insensitive, but it doesn't support partial matches i.e. query "org" wouldn't match to the word "organisation".

I need the search to be able to work with both case-insensitive queries and partial matches.

Am I looking in the wrong direction or asking for too much?

CodePudding user response：

A possible solution in your use case could be using autocomplete with nGram tokenization. It'll allow you to do both partial as well as case-insensitive matches.

The mapping for that can be:

{
  "mappings": {
    "dynamic": false,
    "fields": {
      "name": [
        {
          "type": "string"
        },
        {
          "tokenization": "nGram",
          "type": "autocomplete"
        }
      ]
    }
  }
}

The search query would then look something like this:

{
   "$search":{
      "autocomplete":{
         "query": querySplit,
         "path":"name"
      },
      "index":"search_organizations_name"
   }
}