How to map a class properties in dynamodb without using attribute in .net

Question

I am very new in dynamodb. I am following http://www.rkconsulting.com/blog/persistence-model-framework-with-aws-dynamodb step by step tutorial for connecting and CRUD operation in dynamodb and it`s works fine.

In that tutorial they using attribute mapping for map class properties

[DynamoDBTable("Dinosaur")]
public class Dinosaur
{
    [DynamoDBHashKey]
    public string Id { get; set; }

    [DynamoDBProperty(AttributeName = "Name")]
    public string Name { get; set; }

    [DynamoDBProperty(AttributeName = "HeightMetres")]
    public double HeightMetres { get; set; }

    [DynamoDBProperty(AttributeName = "WeightKG")]
    public double WeightKg { get; set; }

    [DynamoDBProperty(AttributeName = "Age")]
    public int Age { get; set; }

    [DynamoDBProperty(AttributeName = "Characteristics")]
    public List<string> Characteristics { get; set; }

    [DynamoDBProperty(AttributeName = "Photo", Converter = typeof(ImageConverter))]
    public Image Photo { get; set; }

    [DynamoDBIgnore]
    public int IgnoreMe { get; set; }
}

My question is there any way to map class properties without using attribute ?

like as mongoDb

public class Employee
{
    [BsonRepresentation(BsonType.ObjectId)]
    public string Id { get; set; }
}

we can write this in this way in a separate class

BsonClassMap.RegisterClassMap<Employee>(cm => {
  cm.AutoMap();
  cm.IdMemberMap.SetRepresentation(BsonType.ObjectId);
});

Is it possible in dynamodb ?

Answer 1

In the latest version of the .NET SDK you don't have to put in the attribute tags, it will see all read/write properties and upload the attributes as the same name. You would only have to use the [DynamoDBProperty(...)] if you want the attribute name in DynamoDB to be something other than the .NET object name.

So in your case you could simply remove that attribute for all properties except photo (which needs the converter, you could remove the AttributeName part of it) and WeightKg (because the capitalization is different) and you would get the same result.

I see this is a little bit older question now, so it may not have been that way in older versions (not sure) but I'm using 3.3.0.0 of the SDK and it does work that way. You have probably moved on but answering for others that may come upon this thread as I did...

Answer 2

There is no way, the default "strongly typed" client relies on attributes.

If you have time to do the plumbing yourself - there is nothing stopping your from doing your own implementation of the POC to Dynamo mapping though. Amazon client api (AWSSDK.DynamoDBv2) exposes the raw class AmazonDynamoDBClient which handles all the API calls and the DynamoDBConext is just implementation of IDynamoDBContext interface - which exposes all the "strongly typed" operations. So you can make your own implementation and take different mapping approach in it.

Also you can make a feature request for this: https://github.com/aws/aws-sdk-net/issues