DynamoDB - Get Item by Global Secondary Index

Question

I have an existing table which has 10 fields. Fields are like this:

AuthID, UserID, Age, Job, .etc

The table stores data of my users. "AuthID" is primary key and "UserID" is a Global Secondary Index.

When I get item by AuthID, everything is fine. But I can't get item by UserID. I tried GetItem, Query and Scan methods but I failed in all three method.

I need to be able to get data with these 3 methods I wrote below :

1 - Get user data by AuthID (It's already works fine)
2 - Get user data by UserID
3 - Get user data by AuthID and UserID both

AuthID and UserID is unique. Can someone point me right way as to what to do?

Can you update the question with the code you're using to fetch the data? — Seth Geoghegan

Shikhar Shukla Shikhar Shukla · Accepted Answer · 2021-04-08T14:58:38

I have searched a lot in the documentation and found that if you need to get a single item even then you cant use the get or getItem method when using a global secondary index. One can use the query method. a sample of query method with global secondary index is

let params = {
  TableName: "Users",
  IndexName: "your-index",
  ExpressionAttributeValues: {
    ":v1": "myid"
  }, 
  KeyConditionExpression: "my_partition_key_in_gsi = :v1", 
};
 dynamodb.query(params, function(err, data) {
   if (err) console.log(err, err.stack); // an error occurred
   else     console.log(data);           // successful response
 });

DynamoDB - Get Item by Global Secondary Index

1 Answers