Creating MongoDB Unique Key with C#

Question

I am fighting to create a unique field EmailAddress. I\'ve already seen in forums that I have to create an index, but it didn\'t work out for me so far. Does an

Answer 1

In my opinion a better and more feasible way to do this is by creating a custom attribute, then with c# you could get the properties decorated with that attribute and add a unique index, this approach would be generic and very simple to use. Example below:

My custom attribute: MongoUniqueStringIndex

 public class DynamicFieldConfig
{
    public string InputType { get; set; }
    [MongoUniqueStringIndex]
    public string Name { get; set; }
    public string Label { get; set; }
    public List Options { get; set; } = new List();
    public string LookupTypeName { get; set; }
    public int Type { get; set; } //int to enum
    public string Value { get; set; }
    public List Validations { get; set; } = new List();
}

then where you get the collection, for example in my Data Access class I do this:

        public MongoDataAccess(IDatabaseSettings settings)
    {
        // todo: create a connection service/factory to get connection
        var client = new MongoClient(settings.ConnectionString);
        var database = client.GetDatabase(settings.DatabaseName);
        
        var entityName = new Pluralizer().Pluralize(typeof(TMongoEntity).Name);
        _entityStore = database.GetCollection(entityName);

        var uniqueStringIndexProperties = typeof(TMongoEntity).GetProperties().Where(
            prop => Attribute.IsDefined(prop, typeof(MongoUniqueStringIndex))).ToList();
        if (uniqueStringIndexProperties.Any())
            foreach (var propertyInfo in uniqueStringIndexProperties)
            {
                var options = new CreateIndexOptions { Unique = true };
                var propertyInfoName = propertyInfo.Name;
                var field = new StringFieldDefinition(propertyInfoName);
                var indexDefinition = new IndexKeysDefinitionBuilder().Ascending(field);
                var indexModel = new CreateIndexModel(indexDefinition, options);
                _entityStore.Indexes.CreateOne(indexModel);
            }
    }