How to Create Dynamic Itab.

Hi Experts,

I want to create Multiple itabs based on User Selection 

TYPES : BEGIN OF ty_mara,

              matnr TYPE mara-matnr,

              END OF ty_mara.

DATA : lr_data TYPE REF TO data,

           lv_str(20)  TYPE c.

PARAMETERS : p_num TYPE n.     

FIELD-SYMBOLS : <lt_mara> TYPE STANDARD TABLE,

                             <fs> TYPE any.

CREATE DATA lr_data  TYPE STANDARD TABLE OF ty_mara.

ASSIGN lr_data->* TO <lt_mara>.

DO p_num TIMES.

   CONCATENATE '<lt_mara' p_num '>' INTO lv_str.

   ASSIGN lr_data->* to (lv_str). 

ENDDO.

But is Showing an error that lv_str is Unknown . How to Create Multiple Itabs Based on User Selection .

Please Provide if there is any alternative way.

Thanks & Regards,

Raghunadh.K