DYNDB013: Collection property cannot be key

Field	Value
Code	DYNDB013
Severity	Error

Message

Collection property '{0}' in entity '{1}' cannot be marked as partition key or sort key

Description

Collection properties represent multiple values and cannot be used as DynamoDB keys. DynamoDB keys must be scalar values (string, number, or binary).

Example

The following code triggers this diagnostic:

[DynamoDbTable("Orders")]
public partial class Order
{
    [PartitionKey]
    [DynamoDbAttribute("pk")]
    public List<string> Pk { get; set; } = new();

    [DynamoDbAttribute("status")]
    public string Status { get; set; } = string.Empty;
}

Fix

The corrected version:

[DynamoDbTable("Orders")]
public partial class Order
{
    [PartitionKey]
    [DynamoDbAttribute("pk")]
    public string Pk { get; set; } = string.Empty;

    [DynamoDbAttribute("tags")]
    public List<string> Tags { get; set; } = new();

    [DynamoDbAttribute("status")]
    public string Status { get; set; } = string.Empty;
}