In a scripted data set in BIRT you don’t need to define parameters that are bound to report parameters. That is because you can refer to report parameters directly in the open or fetch script, like in this example of an open script:

cities = [];
if (params["pCOUNTRY"]=="France") {
   cities[0] = "Paris";
   cities[1] = "Marseille";
   cities[2] = "Lille";
} else if (params["pCOUNTRY"]=="USA") {
   cities[0] = "New York";
   cities[1] = "Chicago";
}

When you are dealing with a scripted data set that is bound to a nested table, and you need the parameter value to be a value from the outer table, you’ll need a different approach.

In that case, select the data set, choose Edit data set and add a parameter to the scripted data set.
ssspDsParam

Next, bind a value from the outer table to the parameter. Select the inner table, go to the bindings tab and select the Data Set Parameter Binding button:
ssspDsParamBinding

And finally, write the open script like this:

cities = [];
if (inputParams["pCOUNTRY"]=="France") {
   cities[0] = "Paris";
   cities[1] = "Marseille";
   cities[2] = "Lille";
} else if (inputParams["pCOUNTRY"]=="USA") {
   cities[0] = "New York";
   cities[1] = "Chicago";
}

For some reason it took me some time to find out about the use of inputParams[“datasetParam”]. So I hope that if you are dealing with the same issue, this post has eased your search.

This article describes a way to transform column data into row data with the help of a scripted data set, computed columns and a joint data set.

Most of the time I use SQL to perform the task of transforming columns to rows, but some time ago, when helping out someone on the birt-exchange forums, I needed to come up with a different approach. The poster got his data from a .csv file, so the use of SQL was no option. (See bottom of this post for a SQL based solution).

Problem Description
A pie chart needs to be created based on the data in a .csv file:
Department;Infrastructure;Training;Comms;Consumables
X;100;150;200;125
Y;150;200;150;175

The different types of budgets – Infrastructure, Training, Comms and Consumables – are all in separate columns and have to become the slices of the pie chart. If we take the csv based data set as it is, there is no unique column that can be selected as a values series field.

CSV Data Set
First of all: create a data source and data set on the .csv file. This is pretty straightforward.
Also, add a computed column that will always contain the value 1 and name it join_col. We will need this column when creating the Joint Data Set in one of the next steps.
rtcComputedCol

Scripted Data Set
Next, create a scripted data set that has two columns:

  • join_col
  • col_number

The join_col field will always contain the value 1 and will be used to join this data set to the .csv data set created in the previous step.
The col_number will add up for each row in this data set and the number of rows needs to correspond to the number of columns in the .csv that you want to transform to rows. In this case we need 4 rows as there are 4 types of budget in the .csv file.

To create a scripted data set take these steps:

  • create a new data source → make sure you choose Scripted Data Source and enter an appropriate name, e.g. dsScripted
  • create a new data set → Select dsScripted as the datasource and enter an appropriate name, e.g. dsScriptedData
  • add both join_col and col_number as Integer type columns
  • in the open script of the data set, add this code:
    joinCols = [];
    colNums = [];
    for (i=0;i<=4;i++) {
       joinCols[i] = 1;
       colNums[i] = i+1;
    }
    idx = 0;
    
  • in the fetch script of the data set, add this code:
    if (idx < numCols.length) {
    	row["join_col"] = joinCols[idx];
    	row["column_num"] = colNums[idx];
    	idx++;
    	return true;
    }else{
    	return false;
    }
    
  • If you now Edit the data set and select Preview Results, you should see this:
    rtcDsScriptedResults

Joint Data Set
In the joint data set, we will now join the csv data set and the scripted data set together based on the join_col field that exists in both data sets. Every row in the csv data set is joined to every row in the scripted data set. So for every department there will be 4 rows in this data set:
rtcJointDataset

Next step is to create two computed columns. One will hold the budget type and the other will hold the actual budget on each row. The first column, budgetType, has an expression like this:

switch(row["dsScriptedData::column_num"])
{
case 1:
  "Infrastructure";
  break;
case 2:
  "Training";
  break;
case 3:
   "Commissions";
   break;
case 4:
   "Consumables";
   break;
}

The second column, budget, has an expression like this:

switch(row["dsScriptedData::column_num"])
{
case 1:
  row["dsBudget::Infrastructure"];
  break;
case 2:
  row["dsBudget::Training"];
  break;
case 3:
   row["dsBudget::Comms"];
   break;
case 4:
   row["dsBudget::Consumables"];
   break;
}

This is what you should see when you Edit the data set, select Preview Results and scroll to the right:
rtcJointDatasetPreview

Result
With the joint data that we have created, it’s a piece of cake to create the pie chart. Put the budget column in the Series Definition, the budgetType column in the Category Definition and the dsBudget::Department column in the Optional Grouping:
rtcCreateChart

The result now looks like this:
rtcResult

*SQL Solution
If the data does not come from a csv file, but you are selecting it from a data base, you don’t have to worry about scripted data sets, computed columns and all the other fancy features I mentioned in above article. You can write a query like this and you are ready to move on:

SELECT Department,
       'Infrastructure' as budget_type
       Infrastructure_budget as budget
FROM   your_table
UNION  ALL
SELECT Department,
       'Training' as budget_type
       Training_budget as budget
FROM   your_table
UNION  ALL
SELECT Department,
       'Commissions' as budget_type
       Comms_budget as budget
FROM   your_table
UNION  ALL
SELECT Department,
       'Consumables' as budget_type
       Consumable_budget as budget
FROM   your_table