如何在Dynamo DB中使用条件表达式编写查询

Question

I want to query a dynamo db table for getting company id but the same table need a hash key so my query is something like this.

        var optsq = {
          'ConsistentRead': true,
          'AttributesToGet': ['companyid'],
          TableName : usertable,
          Key : {
            "userid" : {
              "S" : usrname
            },
            "comapnyid" :{
              "S":''
            }
          }
        };

My query will only work if the query has the value of company id as well but i want to get company id how can i achive this. In my node js

dynamodb.getItem(optsq, function(err, compdata) {
  if(err){
    console.log(err);
  }else{
    console.log(compdata);
  }

Answer 1

Instead of getItem , you should do a query , which allows you to specify only the userId .

var optsq  = {
    'ConsistentRead': true,
    TableName : usertable,
    KeyConditionExpression: "userid = :userid",
    ExpressionAttributeValues: { ":userid": usrname },
    ProjectionExpression: "companyid" }