The Dutiful Dead, or: A Tale Of Mixed DataSets

Thank you, the link has been very helpful!

I am leaving here an snippet of how I've changed my piece of code from above, in case somebody else want to have fun 😉

Dim ApplicationDt As DataTable
'Get a connection to the application db
Using dbConnApp As DBConnInfo = BRAPi.Database.CreateApplicationDbConnInfo(si)
	'Perform the query
	ApplicationDt = BRApi.Database.ExecuteSql(dbConnApp, SqlString.ToString, True)
End Using

Dim FrameworkDt As DataTable
'Get a connection to the framework db
Using dbConnFW As DbConnInfo = BRApi.Database.CreateFrameworkDbConnInfo(si)
	'Perform the query
	FrameworkDt = BRApi.Database.ExecuteSql(dbConnFW, "SELECT Name,Email FROM SecUser", True)
End Using

'Create the dataset
Dim dsn As New DataSet("DetailedDataAttachment")
'Add tables
dsn.Tables.add(ApplicationDt)
dsn.Tables.add(FrameworkDt)
'Create the relations
dsn.Relations.Add("CreatedNameRelation", dsn.Tables(0).Columns("CreatedUserName"), dsn.Tables(1).Columns("Name"), False)
dsn.Relations.Add("LastEditedNameRelation", dsn.Tables(0).Columns("LastEditedUserName"), dsn.Tables(1).Columns("Name"), False)

'Initialise string variables
Dim rowString As String = String.Empty
Dim finalString As String = String.Empty

Using writer As New StreamWriter(filePath)
	writer.WriteLine(headerString)
	For Each dataAttachmentRow As DataRow In ApplicationDt.Rows
		rowString = String.Join(",", dataAttachmentRow.ItemArray)
		For Each detailRow1 As DataRow In dataAttachmentRow.GetChildRows("CreatedNameRelation")
			finalString = rowString & "," & detailRow1("Email")
		Next
		For Each detailRow2 As DataRow In dataAttachmentRow.GetChildRows("LastEditedNameRelation")
			finalString = finalString & "," & detailRow2("Email")
		Next
		writer.WriteLine(finalString)
	Next
End Using