/sap-abap

ABAP Dynamic Programming - Complete Reference

Source: https://github.com/SAP-samples/abap-cheat-sheets/blob/main/06_Dynamic_Programming.md

Field Symbols

Declaration and Assignment

" Typed field symbol
FIELD-SYMBOLS <fs> TYPE string.
ASSIGN text TO <fs>.

" Generic field symbols
FIELD-SYMBOLS <any> TYPE any.
FIELD-SYMBOLS <data> TYPE data.
FIELD-SYMBOLS <table> TYPE ANY TABLE.
FIELD-SYMBOLS <struct> TYPE any.

" Inline declaration
ASSIGN text TO FIELD-SYMBOL(<inline_fs>).

Static Assignment

" Assign data object
FIELD-SYMBOLS <fs> TYPE i.
DATA num TYPE i VALUE 100.
ASSIGN num TO <fs>.
<fs> = 200.  " Modifies num

" Assign structure component
FIELD-SYMBOLS <comp> TYPE any.
ASSIGN struc-field TO <comp>.

" Assign internal table line
LOOP AT itab ASSIGNING FIELD-SYMBOL(<line>).
  <line>-field = 'modified'.
ENDLOOP.

READ TABLE itab ASSIGNING <line> INDEX 1.

Dynamic Assignment

" Dynamic component access
DATA(comp_name) = 'FIELD1'.
ASSIGN struc-(comp_name) TO FIELD-SYMBOL(<dynamic>).

" Fully dynamic
DATA: obj_name TYPE string VALUE 'STRUC',
      fld_name TYPE string VALUE 'FIELD1'.
ASSIGN (obj_name)-(fld_name) TO <dynamic>.

" Dynamic table field
LOOP AT itab ASSIGNING <line>.
  ASSIGN COMPONENT comp_name OF STRUCTURE <line> TO FIELD-SYMBOL(<value>).
  IF sy-subrc = 0.
    " Component found
  ENDIF.
ENDLOOP.

" By index
ASSIGN COMPONENT 3 OF STRUCTURE struc TO <comp>.

Checking Assignment

IF <fs> IS ASSIGNED.
  " Field symbol points to data
ENDIF.

IF <fs> IS NOT ASSIGNED.
  " Not assigned
ENDIF.

" Unassign
UNASSIGN <fs>.

Casting

" Cast to specific type
ASSIGN dref->* TO <fs> CASTING TYPE string.

" Cast with type object
DATA(type) = cl_abap_typedescr=>describe_by_name( 'STRING' ).
ASSIGN dref->* TO <fs> CASTING TYPE HANDLE type.

Data References

Declaration and Creation

" Typed reference
DATA dref TYPE REF TO string.

" Generic reference
DATA dref TYPE REF TO data.

" REF operator
DATA text TYPE string VALUE 'hello'.
dref = REF #( text ).

" NEW operator
dref = NEW string( 'created' ).
dref = NEW i( 42 ).

" CREATE DATA
CREATE DATA dref TYPE string.
CREATE DATA dref TYPE TABLE OF string.
CREATE DATA dref TYPE zdemo_struc.

" Dynamic type
CREATE DATA dref TYPE (type_name).
CREATE DATA dref TYPE TABLE OF (type_name).

Dereferencing

" Direct access
DATA(value) = dref->*.

" Modification
dref->* = 'new value'.

" With field symbol
ASSIGN dref->* TO FIELD-SYMBOL(<fs>).
<fs> = 'modified'.

" Component access (structures)
DATA(comp_value) = dref->*-component.
dref->*-component = 'value'.

Checking References

IF dref IS BOUND.
  " Reference points to data
ENDIF.

IF dref IS NOT BOUND.
  " Reference is initial
ENDIF.

IF dref IS INITIAL.
  " Same as NOT BOUND
ENDIF.

" Clear reference
CLEAR dref.
FREE dref.

RTTI (Run-Time Type Information)

Type Description Classes

" Get type descriptor
DATA(tdo) = cl_abap_typedescr=>describe_by_data( data_object ).
DATA(tdo) = cl_abap_typedescr=>describe_by_name( 'ZDEMO_STRUC' ).
DATA(tdo) = cl_abap_typedescr=>describe_by_data_ref( dref ).
DATA(tdo) = cl_abap_typedescr=>describe_by_object_ref( oref ).

" Type kind
DATA(kind) = tdo->kind.
" C = Class, E = Elementary, S = Structure, T = Table

" Type name
DATA(name) = tdo->get_relative_name( ).
DATA(abs_name) = tdo->absolute_name.

Elementary Types (CL_ABAP_ELEMDESCR)

DATA(elem) = CAST cl_abap_elemdescr(
  cl_abap_typedescr=>describe_by_data( some_var ) ).

DATA(type_kind) = elem->type_kind.    " I, C, N, D, T, STRING, etc.
DATA(length) = elem->length.
DATA(decimals) = elem->decimals.
DATA(output_length) = elem->output_length.

Structure Types (CL_ABAP_STRUCTDESCR)

DATA(struct_desc) = CAST cl_abap_structdescr(
  cl_abap_typedescr=>describe_by_data( some_struct ) ).

" Get components
DATA(components) = struct_desc->components.
" Returns: name, type_kind, length, decimals, etc.

" Get component names
DATA(comp_names) = struct_desc->get_component_names( ).

" Get component type
DATA(comp_type) = struct_desc->get_component_type( 'FIELD1' ).

Table Types (CL_ABAP_TABLEDESCR)

DATA(table_desc) = CAST cl_abap_tabledescr(
  cl_abap_typedescr=>describe_by_data( some_itab ) ).

DATA(table_kind) = table_desc->table_kind.
" STANDARD, SORTED, HASHED

DATA(line_type) = table_desc->get_table_line_type( ).
DATA(key_info) = table_desc->get_keys( ).
DATA(key_components) = table_desc->key.

Class Types (CL_ABAP_CLASSDESCR)

DATA(class_desc) = CAST cl_abap_classdescr(
  cl_abap_typedescr=>describe_by_object_ref( oref ) ).

DATA(class_name) = class_desc->get_relative_name( ).
DATA(methods) = class_desc->methods.
DATA(attributes) = class_desc->attributes.
DATA(interfaces) = class_desc->interfaces.
DATA(superclass) = class_desc->get_super_class_type( ).

Interface Types (CL_ABAP_INTFDESCR)

DATA(intf_desc) = CAST cl_abap_intfdescr(
  cl_abap_typedescr=>describe_by_name( 'ZIF_MY_INTERFACE' ) ).

DATA(methods) = intf_desc->methods.
DATA(attributes) = intf_desc->attributes.

RTTC (Run-Time Type Creation)

Create Elementary Types

" Built-in types
DATA(string_type) = cl_abap_elemdescr=>get_string( ).
DATA(int_type) = cl_abap_elemdescr=>get_i( ).
DATA(char_type) = cl_abap_elemdescr=>get_c( p_length = 10 ).
DATA(numc_type) = cl_abap_elemdescr=>get_n( p_length = 8 ).
DATA(packed_type) = cl_abap_elemdescr=>get_p( p_length = 8 p_decimals = 2 ).

" Create data with type handle
CREATE DATA dref TYPE HANDLE string_type.

Create Structure Types

" Define components
DATA(components) = VALUE cl_abap_structdescr=>component_table(
  ( name = 'ID' type = cl_abap_elemdescr=>get_i( ) )
  ( name = 'NAME' type = cl_abap_elemdescr=>get_string( ) )
  ( name = 'AMOUNT' type = cl_abap_elemdescr=>get_p( p_length = 8 p_decimals = 2 ) ) ).

" Create structure type
DATA(struct_type) = cl_abap_structdescr=>create( components ).

" Create data
CREATE DATA dref TYPE HANDLE struct_type.
ASSIGN dref->* TO FIELD-SYMBOL(<struct>).

" Access components dynamically
ASSIGN COMPONENT 'NAME' OF STRUCTURE <struct> TO FIELD-SYMBOL(<name>).
<name> = 'Test'.

Create Table Types

" From structure type
DATA(table_type) = cl_abap_tabledescr=>create(
  p_line_type = struct_type
  p_table_kind = cl_abap_tabledescr=>tablekind_std
  p_unique = abap_false ).

" With key
DATA(sorted_table) = cl_abap_tabledescr=>create(
  p_line_type = struct_type
  p_table_kind = cl_abap_tabledescr=>tablekind_sorted
  p_unique = abap_true
  p_key = VALUE #( ( name = 'ID' ) ) ).

" Create table data
CREATE DATA dref TYPE HANDLE table_type.
ASSIGN dref->* TO FIELD-SYMBOL(<table>).

Dynamic SQL

" Dynamic table name
DATA table_name TYPE string VALUE 'ZDEMO_TABLE'.
SELECT * FROM (table_name) INTO TABLE @DATA(result).

" Dynamic field list
DATA field_list TYPE string VALUE 'CARRID, CONNID, FLDATE'.
SELECT (field_list) FROM zdemo_fli INTO TABLE @DATA(fields).

" Dynamic WHERE clause
DATA where_clause TYPE string VALUE `CARRID = 'LH'`.
SELECT * FROM zdemo_fli WHERE (where_clause) INTO TABLE @DATA(filtered).

" Dynamic ORDER BY
DATA order_by TYPE string VALUE 'FLDATE DESCENDING'.
SELECT * FROM zdemo_fli ORDER BY (order_by) INTO TABLE @DATA(sorted).

" Fully dynamic
SELECT (field_list)
  FROM (table_name)
  WHERE (where_clause)
  ORDER BY (order_by)
  INTO TABLE @DATA(dynamic_result).

Dynamic Method Calls

" Dynamic method name
DATA method_name TYPE string VALUE 'PROCESS'.
CALL METHOD oref->(method_name).

" With parameters
DATA(ptab) = VALUE abap_parmbind_tab(
  ( name = 'IV_INPUT' kind = cl_abap_objectdescr=>exporting value = REF #( input ) )
  ( name = 'RV_RESULT' kind = cl_abap_objectdescr=>returning value = REF #( result ) ) ).

CALL METHOD oref->(method_name) PARAMETER-TABLE ptab.

" Dynamic class instantiation
DATA class_name TYPE string VALUE 'ZCL_MY_CLASS'.
CREATE OBJECT oref TYPE (class_name).

" With constructor parameters
DATA(ctab) = VALUE abap_parmbind_tab(
  ( name = 'IV_PARAM' kind = cl_abap_objectdescr=>exporting value = REF #( param ) ) ).

CREATE OBJECT oref TYPE (class_name) PARAMETER-TABLE ctab.

Dynamic Function Calls

DATA func_name TYPE string VALUE 'Z_MY_FUNCTION'.

DATA(ptab) = VALUE abap_func_parmbind_tab(
  ( name = 'IV_INPUT' kind = abap_func_exporting value = REF #( input ) )
  ( name = 'EV_OUTPUT' kind = abap_func_importing value = REF #( output ) )
  ( name = 'CT_TABLE' kind = abap_func_tables value = REF #( table ) ) ).

DATA(etab) = VALUE abap_func_excpbind_tab(
  ( name = 'NOT_FOUND' value = 1 )
  ( name = 'OTHERS' value = 99 ) ).

CALL FUNCTION func_name
  PARAMETER-TABLE ptab
  EXCEPTION-TABLE etab.

IF sy-subrc <> 0.
  " Handle exception
ENDIF.

Generic Types Reference

Best Practices

1. Check assignments before using field symbols
2. Check references before dereferencing
3. Use RTTI for type inspection
4. Use RTTC for dynamic type creation
5. Handle sy-subrc after dynamic operations
6. Validate dynamic names to prevent injection
7. Prefer static typing when possible for performance
8. Document dynamic code thoroughly