如何从node.js访问dynamo db

Question

I want access the Data of Amazon Data server from Node.js on specific primary key value. The Data is Available in the form:

{
  "Count": 9862,
  "Items": [
    {
      "Admin": {
        "S": "false"
      },
      "UserId": {
        "S": "e9633477-978e-4956-ab34-cc4b8bbe4adf"
      },
      "Age": {
        "N": "76.24807963806055"
      },
      "Promoted": {
        "S": "true"
      },
      "UserName": {
        "S": "e9633477"
      },
      "Registered": {
        "S": "true"
      }
    },
    {
      "Admin": {
        "S": "false"
      },
      "UserId": {
        "S": "acf3eff7-36d6-4c3f-81dd-76f3a8071bcf"
      },
      "Age": {
        "N": "64.79224276370684"
      },
      "Promoted": {
        "S": "true"
      },
      "UserName": {
        "S": "acf3eff7"
      },
      "Registered": {
        "S": "true"
      }
    },

Everytime when I am Making Request with the code:

app.get('/Mydetails/:tablename/:id', function(req, res){
console.log('Table is ' + req.params.tablename);


var element = {TableName: req.params.tablename, Key:{UserID:{"S": '"'+req.params.id+'"' }}};
 console.log('Id is "' + req.params.id + '"');
dynamodb.getItem(element, function(err, data){
    if(err){
        console.log('Error occurred: '+err);
    }else{
     console.log('succeed');
        res.json(data);
    }
});

then it gives the following error:

**ValidationException: The provided key element does not match the schema.**

However I have tried this also-

var element = {TableName: req.params.tablename, Key:{UserId:{"S": +req.params.id}}};

Any Idea? Any help will be Appreciated.

Answer 1

You have to also pass the range key if it exists in the 'Key', for the parameters

example it should be

Key:{'thePrimaryKey':{ "S": 'primaryKey' }, 'theRangeKey': {'S': 'rangeKey'} }

Hope this helps!

Answer 2

It appears you are sending a variable named params which I don't see where you populate it.

You should be sending element : dynamodb.getItem(element, callback)

Answer 3

Looks like there is a typo (case difference) in your UserID (vs UserId). - Upper case D. Give a try with this change.