ABAP CORRESPONDING: Map Structures and Tables

CORRESPONDING <type>(
  <source>
  [ BASE ( <base> ) ]
  [ MAPPING <target1> = <source1> ... ]
  [ EXCEPT <field1> <field2> ... ]
)

TYPES: BEGIN OF ty_source,
         id    TYPE i,
         name  TYPE string,
         email TYPE string,
       END OF ty_source,

       BEGIN OF ty_target,
         id      TYPE i,
         name    TYPE string,
         address TYPE string,
       END OF ty_target.

DATA: ls_source TYPE ty_source,
      ls_target TYPE ty_target.

ls_source = VALUE #( id = 1 name = 'Max' email = '[email protected]' ).

" Fields with same names are copied
ls_target = CORRESPONDING #( ls_source ).

" ls_target-id = 1
" ls_target-name = 'Max'
" ls_target-address = '' (not present in source)
" email is ignored (not present in target)

" Classic
MOVE-CORRESPONDING ls_source TO ls_target.

" Modern (functionally equivalent)
ls_target = CORRESPONDING #( ls_source ).

" The difference: CORRESPONDING is an expression
" and can be used in other expressions
DATA(ls_result) = CORRESPONDING ty_target( ls_source ).

ls_target = VALUE #( id = 99 name = 'Old' address = 'Berlin' ).

" WITHOUT BASE: address becomes initial
ls_target = CORRESPONDING #( ls_source ).
" ls_target-address = ''

" WITH BASE: address is preserved
ls_target = VALUE #( id = 99 name = 'Old' address = 'Berlin' ).
ls_target = CORRESPONDING #( BASE ( ls_target ) ls_source ).
" ls_target-address = 'Berlin'

TYPES: BEGIN OF ty_db_record,
         kunnr TYPE kunnr,
         name1 TYPE string,
         ort01 TYPE string,
       END OF ty_db_record,

       BEGIN OF ty_customer,
         customer_id   TYPE kunnr,
         customer_name TYPE string,
         city          TYPE string,
       END OF ty_customer.

DATA: ls_db_record TYPE ty_db_record,
      ls_customer  TYPE ty_customer.

ls_db_record = VALUE #( kunnr = '1000' name1 = 'Miller Inc.' ort01 = 'Berlin' ).

" With MAPPING: Map field names
ls_customer = CORRESPONDING #(
  ls_db_record
  MAPPING customer_id   = kunnr
          customer_name = name1
          city          = ort01
).

" ls_customer-customer_id = '1000'
" ls_customer-customer_name = 'Miller Inc.'
" ls_customer-city = 'Berlin'

TYPES: BEGIN OF ty_user,
         id       TYPE i,
         name     TYPE string,
         password TYPE string,
         email    TYPE string,
       END OF ty_user.

DATA: ls_user_full TYPE ty_user,
      ls_user_safe TYPE ty_user.

ls_user_full = VALUE #(
  id = 1 name = 'Admin' password = 'secret' email = '[email protected]'
).

" Do NOT copy password
ls_user_safe = CORRESPONDING #( ls_user_full EXCEPT password ).

" ls_user_safe-password = '' (not copied)

TYPES: BEGIN OF ty_order_db,
         aufnr    TYPE string,
         kdnr     TYPE string,
         datum    TYPE d,
         internal TYPE string,  " Internal field
       END OF ty_order_db,

       BEGIN OF ty_order_api,
         order_id      TYPE string,
         customer_id   TYPE string,
         order_date    TYPE d,
       END OF ty_order_api.

DATA: ls_order_db  TYPE ty_order_db,
      ls_order_api TYPE ty_order_api.

ls_order_db = VALUE #(
  aufnr = 'ORD001' kdnr = 'C100' datum = sy-datum internal = 'XYZ'
).

ls_order_api = CORRESPONDING #(
  ls_order_db
  MAPPING order_id    = aufnr
          customer_id = kdnr
          order_date  = datum
  EXCEPT internal
).

TYPES: ty_source_tab TYPE TABLE OF ty_source WITH EMPTY KEY,
       ty_target_tab TYPE TABLE OF ty_target WITH EMPTY KEY.

DATA: lt_source TYPE ty_source_tab,
      lt_target TYPE ty_target_tab.

lt_source = VALUE #(
  ( id = 1 name = 'Anna'  email = '[email protected]' )
  ( id = 2 name = 'Bernd' email = '[email protected]' )
  ( id = 3 name = 'Clara' email = '[email protected]' )
).

" Transform entire table
lt_target = CORRESPONDING #( lt_source ).

" With MAPPING
lt_target = CORRESPONDING #(
  lt_source
  MAPPING id = id name = name
).

TYPES: BEGIN OF ty_address,
         street TYPE string,
         city   TYPE string,
       END OF ty_address,

       BEGIN OF ty_person_full,
         name    TYPE string,
         address TYPE ty_address,
         items   TYPE TABLE OF string WITH EMPTY KEY,
       END OF ty_person_full.

DATA: ls_source TYPE ty_person_full,
      ls_target TYPE ty_person_full.

ls_source = VALUE #(
  name = 'Max'
  address = VALUE #( street = 'Main St.' city = 'Berlin' )
  items = VALUE #( ( `Item1` ) ( `Item2` ) )
).

" DEEP also copies nested structures and tables
ls_target = CORRESPONDING #( DEEP ls_source ).

METHODS: process_order
  IMPORTING is_api_order TYPE ty_order_api.

" Call with transformation
process_order(
  is_api_order = CORRESPONDING #( ls_db_order
    MAPPING order_id = aufnr
            customer_id = kdnr
  )
).

" Create structure and transform simultaneously
DATA(ls_output) = VALUE ty_order_api(
  BASE CORRESPONDING #( ls_db_order
    MAPPING order_id = aufnr
  )
  " Set additional fields
  status = 'NEW'
).

" Combine with FOR and CORRESPONDING
DATA(lt_active_customers) = VALUE ty_customers_api(
  FOR ls_db IN lt_customers_db
  WHERE ( status = 'A' )
  ( CORRESPONDING #( ls_db
      MAPPING customer_id = kunnr
              customer_name = name1
    )
  )
).

" MOVE-CORRESPONDING: Only simple mapping
MOVE-CORRESPONDING ls_source TO ls_target.

" CORRESPONDING: Flexible and powerful
ls_target = CORRESPONDING #(
  BASE ( ls_target )
  ls_source
  MAPPING target_field = source_field
  EXCEPT  unwanted_field
).