包含时间戳的 DynamoDb 级联密钥

Question

I have a DynamoDb table with the following key structure,

Hash     Range
string   string|string|timestamp(string)
12345    ABC|DEF|123456789

I want to be able to get items that have a timestamp which is equal or less than the time stamp part in the range key, but I am not sure whether my implementation is correct or not or if there are edge cases that this doesn't work so I want to get a second opinion.

here is my implementation:

var asyncSearch = _dynamoDbContext.QueryAsync<PricingModel>(entityKeyId,
                    new DynamoDBOperationConfig
                    {
                        OverrideTableName = _config.Value.PricingModelTableNameOverride,
                        QueryFilter = new List<ScanCondition>
                        {
                            new ScanCondition(nameof(PricingModel.EntityKeyId),
                                ScanOperator.Equal,
                                entityKeyId),
                            new ScanCondition(nameof(PricingModel.SortKeyId),
                                ScanOperator.LessThanOrEqual,
                                sortKeyId)
                        }
                    });

Answer 1

There is very little information to go on here (for example what are the other components of the range key, and what will you use them for). However, it looks like you need to move the position of the timestamp to the start of the range key.

DynamoDB will order the items within the partition key by the range key. If you want them date ordered, you will need the timestamp as the first part of the range key.

As your range key is a string, make sure you choose a date format that sorts naturally as a string.

EDIT: ISO 8601 strings (eg 2019-04-11T11:37:00Z) are naturally sortable as a string, and also human readable.

EDIT: You can then use the LT key condition operator for less than, and BEGINS_WITH for an exact timestamp