Sales Order Items Matrix and RDR1 table

Hi,

I have to change values of some columns in SO item matrix.

For e.g, I need to change the 'order quantity' of a particular SO row.

Is there any mapping between RDR1 table, and the matrix row#?

i.e, if I want to change linenum= 3 and Vis_Row = 3 of a RDR1 row, how can I find out which row# in matrix I have to change?

Generally matrix row# is RDR1.Vis_Row+1, but not always.

The exceptions will be: If there is a text comment in SO, or the lines are deleted,...

Please let me know how I can achieve the mapping.

(I dont want to search in all of the matrix lines for a RDR1 match.)

Thanks in advance.

Regards,

Geetha