BODS while loop

Hi

  I am trying to use a while loop to execute a (dataflow to write into a template table)

I have a counter from another template table, say ROW_NO. I have to execute the dataflow in increments of 50 rows until all the ROW_NO are executed.

How can I do that?

Also how can I write to the same template table or append the data without losing the data during the while loop execution?

I am using BODS 14.1.1.210.

Cheers!