Compare values in dynamodb during query without knowing values in ExpressionAttributeValues

Question

Is it possible to apply a filter based on values inside a dynamodb database? Let's say the database contains an object info within a table:

info: {
    toDo: x,
    done: y,
}

Using the ExpressionAttributeValues, is it possible to check whether the info.toDo = info.done and apply a filter on it without knowing the current values of info.toDo and info.done ?

At the moment I tried using ExpressionAttributeNames so it contains:

'#toDo': info.toDo, '#done': info.done'

and the filter FilterExpression is

#toDo = #done

but I'm retrieving no items doing a query with this filter.

Thanks a lot!

It seems like there is no option for this in DynamoDB :(

Rajesh Kaushik
– Rajesh Kaushik

2022-07-19 04:29:18 +00:00
Commented Jul 19, 2022 at 4:29 — Rajesh Kaushik
– Rajesh Kaushik, Commented Jul 19, 2022 at 4:29

Guy · Accepted Answer · 2022-07-19 05:16:51Z

0

DynamoDB is not designed to perform arbitrary queries as you might be used to in a relational database. It is designed for fast lookups based on keys.

Therefore, if you can add an index allowing you to access the records you look for, you can use it for this new access pattern. For example, if you add an index that uses info.toDo as the partition key and info.done as the sort key. You can then use the index to scan the records with the conditional expression of PK=x and SK=x, assuming that the list of possible values is limited and known.

answered Jul 19, 2022 at 5:16

Guy

13k3 gold badges51 silver badges67 bronze badges

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

Collectives™ on Stack Overflow

Compare values in dynamodb during query without knowing values in ExpressionAttributeValues

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related