creating group and analyzing data from array list in birt

Question

I am using mongo db in birt reports. I have data set which contains an array of object like in the picture.

deviceStatus is an array which contains child object

Answer 1

Please follow below steps to get the desired response.

Data:

db.devicestatus.insert([
  {
    "_id": "0001",
    "className":"store",
    "deviceStatus": [ {
    "deviceName": "CardReader",
    "errorCode": "97080301",
    "status": "Bad"
  },
  {
    "deviceName": "CashAcceptor",
    "errorCode": "97080302,97080303",
    "status": "Bad"
  },
  {
    "deviceName": "CashDispenser",
    "errorCode": "",
    "status": "Good"
  }]
  }
])

1.Data Explorer - Go to Data Sets - New Data Set - Select Data Source - Input Data Set Name - Click Next

2.Input collection name - devicestatus - Lists all the fields - Select Aggregate option from the command type dropdown - Click Expression

3.Add the below expression in the expression builder prompt - Click OK

The below expression $unwind to flatten the array to decompose devicestatus array into documents followed by $project to keep the required fields.

[
  {"$unwind":"$deviceStatus"},
  {"$project":{
    "_id":0,
    "className":1,
   "deviceStatus.deviceName":1,
   "deviceStatus.errorCode":1
   }
  }
]

OR

The below expression iterates over devicestatus array and $map and $project the required fields followed by $unwind to flatten to decompose the array into documents.

[{
  "$project":{
    "_id":0,
    "className":1, 
    "deviceStatus":{
      "$map":{
        "input":"$deviceStatus",
        "as":"result",
        "in":{
          "deviceName":"$$result.deviceName",
          "errorCode":"$$result.errorCode"
        }
      }
    }
   }
 },
 {"$unwind":"$deviceStatus"}
]

OR

4.Confirm to refresh - Click yes

5.Move all available fields to the selected multi select drop box - Click Finish

6.Preview Results

{"className":"store", "deviceStatus":{"deviceName":"CardReader","errorCode":"97080301"}}
{"className":"store", "deviceStatus":{ "deviceName":"CashAcceptor","errorCode":"97080302,97080303"}}
{"className":"store","deviceStatus":{"deviceName":"CashDispenser","errorCode":""}}