getItem 时出现 aws DynamoDB 问题

Question

I am trying to get single Item through dynamoDB using Javascript here my code

var params = {
    TableName: 'sharedata',
    Key: {
        id: _id
    },
    ProjectionExpression: 'ATTRIBUTE_NAME'
    };

ddb.getItem(params, function(err, data) {
    if (err) {
        console.log("Error", err);
    } else {
        console.log("Success", data.Item);
    }
    });

and here my table in dynamoDB.

I am facing error: Expected params.Key['id'] to be a structure. What I am missing I am trying same as per docs reading writing a single Item in dynamoDB

Answer 1

The error

error: Expected params.Key['id'] to be a structure

is indicating that key is not formed correctly in the request. From the docs :

var params = {
  TableName: 'TABLE',
  Key: {
    'KEY_NAME': {N: '001'}
  },
  ProjectionExpression: 'ATTRIBUTE_NAME'
};

Try this out:

var params = {
    TableName: 'sharedata',
    Key: {
        id: {S: _id}
    },
    ProjectionExpression: 'ATTRIBUTE_NAME'
    };

Answer 2

The Object to be formatted in a AttributeValue representation. That means you would have to change this

var params = {
    TableName: 'sharedata',
    Key: {
        id: {S:_id}
    },
    ProjectionExpression: 'ATTRIBUTE_NAME'
 };