Add a condition expression when inserting into DynamoDB.

[igormgomes]

Type: Feature

Is your feature request related to a problem? Please describe.
Is there a way to use a condition expression with DynamoDbOperations for inserting data, or do I need to create a separate implementation of DynamoDbTable, or should I just utilize the DynamoDbClient?

Describe the solution you'd like
Perhaps we can create another method and call it like this.

var conditionalCheck = new ConditionalCheck();
conditionalCheck.setExpression(expression);
dynamoDbOperations.save(entity, conditionalCheck);

Describe alternatives you've considered
I created an implementation using DynamoDbClient, and it worked.

val putItemRequest = PutItemRequest.builder()
            .tableName(tableName)
            .item(item)
            .conditionExpression("attribute_not_exists(my_sk)")
            .build();
dynamoDbClient.putItem(putItemRequest);

[magnuspedro]

I'm having the same issue. I looked up the doc and couldn't find anything. I had to use the same alternative as he did

[arielsapatelli]

I had the same problem using the conditional expressions in dynamodb operations. It would be interesting to externalize this parameter.

[MatejNedic]

Hey @igormgomes, thanks on reporting, I agree we should extend both operations and template with this. Are you willing to make contribution?

[igormgomes]

Hey @MatejNedic, thanks for replying. Yes, I'm willing.

[MatejNedic]

@igormgomes all yours :)

[aagrawal-ipsi-ghub]

@igormgomes Hi I am also facing same issue, are you working on it?

[vyomrastogi]

Hi @MatejNedic , is this issue open for contribution ? I would be willing to take a stab at this.

[maciejwalkowiak]

@vyomrastogi go for it.

[vyomrastogi]

hi @maciejwalkowiak , I would like to discuss the approach, and also looking for any tips you might have for me as a first time contributor so that it makes review easier for you and team.

Based on aws sdk, I think DynamoDBOperation can be enhanced with one of the following convenience methods..

save(PutItemEnhancedRequest<T> enhancedRequest)

The `PutItemEnhancedRequest already has support for conditionalExpression, and any other future enhancement by aws team will get available to devs easily. something like :

# class DynamoDBTemplate 
public <T> T save(PutItemEnhancedRequest<T> enhancedRequest) {
        var item = enhancedRequest.item();
	prepareTable(item).putItem(enhancedRequest);
        return item;
}

save(T entity, ConditionCheck<T> conditionCheck) : as suggested in the issue

This will delegate responsibility of creating PutItemEnhancedRequest to dynamoDBTemplate and perform the save. something like :

# class DynamoDBTemplate 
public <T> T save(T entity, ConditionCheck<T> conditionCheck) {
        // prepare enhancedRequest from entity and conditionCheck 
	prepareTable(entity).putItem(enhancedRequest);
        return item;
}

Do you have a different suggestion ? . Would love to hear your thoughts. Meanwhile I will work towards getting a draft up.