Accessing Table Type

Question

Hi All,
    In the code below WFAT_EMP_INT_EMPWA is a table type.
For the function module 'WFA_EMP_DATA_GET' ,  ET_EMP_WORKAREA is an export parameter of type WFAT_EMP_INT_EMPWA
For the function module 'WFA_EMP_DATA_MODIFY' , IT_EMP_WORKAREA is an import parameter of the same type.
I need to get  the parameter from one function module and pass it to the next function module.
Do i need to create a work area for the table type or can we simply define the table type and just pass it to the next FM as shown below.
DATA: ITAB_WRKAREA TYPE WFAT_EMP_INT_EMPWA.
DATA: itab_bapiret TYPE BAPIRET2_T,
      wa_bapiret TYPE LINE OF BAPIRET2_T.
DATA: itab_bapiret1 TYPE BAPIRET2_T,
       wa_bapiret1 TYPE LINE OF BAPIRET2_T.
FORM GET_WRKAREA_CODE.
  CALL FUNCTION 'WFA_EMP_DATA_GET'
    EXPORTING
      IV_EMP_BPID       = W_BUPNR
      IV_ORG_OBJID      = W_ORGEH
      IV_EFFECTIVE_WEEK = SY-DATUM
      IV_TEMPORARY      = GC_SPACE
    IMPORTING
      ET_EMP_WORKAREA   = ITAB_WRKAREA
      ET_RETURN         = itab_bapiret.
  LOOP AT itab_bapiret
  INTO wa_bapiret.
  WRITE :/ wa_bapiret-MESSAGE.
  ENDLOOP.
ENDFORM.                    "get_wrkarea
FORM TRANSFER_WRKAREA.
  CALL FUNCTION 'WFA_EMP_DATA_MODIFY'
    EXPORTING
      IV_EMP_BPID            = W_BUPNR
      IV_ORG_OBJID           = W_ORGEH
      IV_EFFECTIVE_WEEK      = SY-DATUM
      IS_EMP_INTERFACE_ADMIN = WA_WFAS_EMP_INT_ADMIN
     IT_EMP_WORKAREA        = ITAB_WRKAREA
    IMPORTING
      ET_RETURN              = itab_bapiret1.
      LOOP AT itab_bapiret1
      INTO wa_bapiret1.
      WRITE :/ wa_bapiret1-MESSAGE.
      ENDLOOP.
ENDFORM.                    "transfer_wrkarea
In the above context does ITAB_WRKAREA(table type) will have only one record.
What is the difference between these 2 statements
DATA:  x type TT.   " TT refers to table type
DATA: x type ST.    "ST refers to structure type
I am getting confused with the table types and structures . Table type refers to a line type which inturn refers to a structure? Can some one explain this.
Thanks in Advance

Answer 1

*-- Table type is a table.. when you refere to a table type u need not use again standard table of , or occurs 0 addition the follwoing statmenet will declare x as a internal table with out header line.
DATA: x type TT. " TT refers to table type
*-- Structure is a flat structure and x is a work area not internal table.
DATA: x type ST. "ST refers to structure type
if you have to create x as intenaal table using strrucre ST then
data : x type standard table of ST..
Thanks
Mahesh