How to create a dynamic table?

Question

Hello experts!
I would be very grateful for assistance with a complicated requirement I have gotten.
I am working within a user exit in BI-IP and one of the parameter in the method is a table (whose structure is dynamic):
C_TH_DATA     Changing     Type     HASHED TABLE     Transaction Data
Due to the requirements I have I need to create a table based on the C_TH_DATA table BUT with a few additional fields.
I have posted my first attempt below (it is syntactically correct).
Does my approach make sense???
Grateful for any suggestions.
Greetings,
Martin
method IF_RSPLFA_SRVTYPE_IMP_EXEC_REF~EXECUTE.
  field-symbols:
    <f_ref_data>        type  any,
    <f_interim_data>    type  any,
    <f_new_data>        type  any,
    <f_itab>            type  any table,
    <f_infoprov>        type  RSINFOPROV,
    <f_infoprov_ref>    type  RSINFOPROV,
    <f_ref_data_BCCMP07>  type  any,
    <f_ref_data_BCCMC02>  type  any,
    <f_spc>             type  /bic/oiBHSPC0,
    <f_spc_ref>         type  /bic/oiBHSPC0,
    <f_blcopem1>        type  /bic/oiblcopem1,
    <f_blcopem1_ref>    type  /bic/oiblcopem1,
    <f_blcalpo0>        type  /bic/oiblcalpo0,
    <f_blcalpo0_ref>    type  /bic/oiblcalpo0.
  data:
    l_r_data1            type  ref to data,
    l_r_data2            type  ref to data,
    l_d_sumcostpo        type  f,
    l_d_deltacostpo      type  f,
    l_d_sumdeltacostpo   type  f.
Generate new (empty record)
  create data l_r_data1 like line of c_th_data.
  assign l_r_data1->* to <f_new_data>.
  TYPES:
    BEGIN OF l_modif_c_th_data,
      l_r_itab    type  ref to data,
      thiscostpo  type  /bic/oiblcopem1,
      thiscostto  type  /bic/oiblcopem2,
      thiscostcm  type  /bic/oiblcopem3,
      thismanpo   type  /bic/oiblmansec1,
      thismanto   type  /bic/oiblmansec2,
      thismancm   type  /bic/oiblmansec3,
    END OF l_modif_c_th_data.
  data:
    l_r_itab    type  ref to data.
  create data l_r_itab type table of l_modif_c_th_data.
  assign l_r_itab->* to <f_itab>.
Generate new (empty record)
  create data l_r_data2 type l_modif_c_th_data.
  assign l_r_data2->* to <f_interim_data>.

Answer 1

Hi marcin,
thanks for your answer.
Im trying your examples ( /people/marcin.pciak/blog/2010/09/09/do-you-really-know-everything-about-typing--part-2 ) but your example dumps.
DATA gr_elemdescr_p   TYPE REF TO cl_abap_elemdescr.
DATA gr_elemdescr_i   TYPE REF TO cl_abap_elemdescr.
DATA: gt_components   TYPE cl_abap_structdescr=>component_table,
        wa_component    LIKE LINE OF gt_components.
  DATA: gr_structdescr  TYPE REF TO cl_abap_structdescr.
  wa_component-name = 'HEADCOUNT'.
  wa_component-type = gr_elemdescr_i.
  APPEND wa_component TO gt_components.
  wa_component-name = 'CAPACITY'.
  wa_component-type = gr_elemdescr_p.
  APPEND wa_component TO gt_components.
  gr_structdescr = cl_abap_structdescr=>create( gt_components ).  <= causes error CX_SY_STRUCT_COMP_TYPE
DATA gr_data TYPE REF TO data.
  CREATE DATA gr_data TYPE HANDLE gr_structdescr.
I suspect Im doin something wrong.