DynamoDB/Dynamoose error using query with .in() operator

Question

I'm creating a chat application and using Dynamoose.js. I have a conversations table and a messages table. I want to query on the messages table to find all messages belonging to a conversation. When I make the query, I'm getting the following error:

message: 'Invalid operator used in KeyConditionExpression: IN',
code: 'ValidationException',

Here's what my schemas and query looks like:

conversation.model.js

let schema = {
        conversation_id: {
            hashKey: true,
            type: String,
            required: true
        },

        participants: {
            type: Array,
            schema: [String],
            required: true
        },

        lastModified: {
            type: Date,
            required: true,
            default: Date.now
        }
    };

message.model.js

let schema = {
        message_id: {
            hashKey: true,
            type: String,
            required: true,
            index: {
                name: 'conversationIndex',
                global: true,
                rangeKey: 'conversation_id',
                throughput: {'read': 10, 'write': 10}
            }
        },

        conversation_id: {
            rangeKey: true,
            type: String,
            required: true
        },

        from: {
            type: String,
            required: true
        },     

        message: {
            type: String,
            required: true
        },

        ts: {
            type: Date,
            required: true,
            default: Date.now
        }

query

Message.query('conversation_id').in(userConversations).using('conversationIndex').exec((err, messages) => {
     // userConversations is an array of conversation_id's

     if (err) {
          console.error(err);
     } else {

     }
});

Any idea of where I'm going wrong here? I think it may be related to how I'm creating and using the secondary indexes, but I'm not quite sure. Any help is appreciated, thanks!

Answer 1

DynamoDB queries require you to query for where hashKey = ______. You can't do a query where you query for a hashKey using in.

On top of that, conversation_id isn't a hashKey in your index.

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Kinda hard to tell, but it looks like this is a symptom of DB design that doesn't fit with DynamoDB patterns. I'd suggest looking more into DynamoDB table design, and redesigning your table to better fit within DynamoDB patterns.