DynamoDB query doesn't return all attributes

Question

I have a table in DynamoDB.

Table name  test-vod
Primary partition key   guid (String)
Primary sort key    -

With additional attributes as you can see below.

The goal is to query the table using one of the columns that are not a primary key srcVideo, to accomplish that we created a second local index.

And using the low-level API from DynamoDB SDK NuGet package we query with the below code (open to other options instead of low-level API).

var queryRequest = new QueryRequest
            {
                TableName = $"{_environmentName}-vod",
                IndexName = "srcVideo-index",
                ScanIndexForward = true,
                KeyConditionExpression = "srcVideo = :v_srcVideo",
                ExpressionAttributeValues = new Dictionary<string, AttributeValue>()
                {
                    {":v_srcVideo",new AttributeValue {S = inputMediaKey}}
                }
            };

            var response = await _client.QueryAsync(queryRequest, cancellationToken);

            // Does not exist
            var hlsUrl = response.Items
                .SelectMany(p => p)
                .SingleOrDefault(p => p.Key.Equals("hlsUrl"));

I am interested to retrieve 3 attributes (fields) from the response hlsUrl, dashUrl, workflowsStatus but all 3 missing, the response contains a Dictionary with a count of keys 27, these are only 27 out of the 35 available columns.

I have tried using ProjectionExpression and other query combinations with no success.

Charles · Accepted Answer · 2020-03-11 18:54:58Z

3

You don't show the CREATE TABLE you've used...

Sounds like your index wasn't created with the Projection attribute you really want...

Default is , KEYS_ONLY. Sounds like you want ALL or maybe INCLUDE just selected attributes...GlobalSecondaryIndex - Projection

Local secondary indexes work the same way...

answered Mar 11, 2020 at 18:54

Charles

24.2k3 gold badges23 silver badges50 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

xplat Over a year ago

It is interesting but I made it work with the posted answer, even if the key/value is not present in the debugger you can still retrieve it.

xplat · Accepted Answer · 2020-03-11 21:51:27Z

It is interesting but I made it work with the below code, even if the key/value is not present in the dictionary when inspecting the debugger you can still retrieve it.

var queryRequest = new QueryRequest
            {
                TableName = tableName,
                IndexName = "srcVideo-index",
                ScanIndexForward = true,
                KeyConditionExpression = "srcVideo = :v_srcVideo",
                ExpressionAttributeValues = new Dictionary<string, AttributeValue>()
                {
                    {":v_srcVideo", new AttributeValue {S = inputMediaKey}}
                }
            };

            var response = await _client.QueryAsync(queryRequest, cancellationToken);

            if (response.Items.AnyAndNotNull())
            {
                var dictionary = response.Items.First().ToDictionary(p => p.Key, x => x.Value.S);

                return Result.Ok (new VodDataInfo(
                    dictionary["srcBucket"],
                    dictionary["srcVideo"],
                    dictionary["destBucket"],
                    dictionary.ContainsKey("dashUrl") 
                        ? dictionary["dashUrl"] 
                        : default,
                    dictionary.ContainsKey("hlsUrl") 
                        ? dictionary["hlsUrl"] 
                        : default,
                    dictionary["workflowStatus"]));
            }

Collectives™ on Stack Overflow

DynamoDB query doesn't return all attributes

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related