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APPEND

Short Reference

Other versions: 7.31 | 7.40 | 7.54

Syntax


APPEND line_spec TO itab [SORTED BY comp] [result].

Addition

... SORTED BY comp

Effect

This statement appends one or more rows line_spec to an internal index table itab. It is appended so that a new last row is created with regard to the primary table index.

If itab is a standard table, SORTED BY can be used to sort the table in a specified way. Use result when appending a single row to set a reference to the appended row in the form of a field symbol or a data reference.

For the individual table types, appending is done as follows:

  • To standard tables, rows are appended directly and without checking the content of the internal table.
  • Rows are appended to sorted tables only if they match the sort order and do not create duplicate entries (if the primary table key is unique).
  • No rows can be appended to hashed tables.

Exceptions are raised in the following cases:

  • If a row to be appended would produce a duplicate entry in a unique primary table key, a non-handleable exception is raised.
  • If a row to be appended would produce a duplicate entry in a unique secondary table key, a handleable exception of the class CX_SY_ITAB_DUPLICATE_KEY is raised.
  • If a block of rows to be appended would produce a duplicate entry in a unique secondary table key, a non-handleable exception is raised.
  • If the row being appended would destroy the sort order of sorted tables, a non-handleable exception is raised (the secondary index of a sorted secondary key, however, is updated before it is used again).

System Fields

The APPEND statement sets sy-tabix to the row number of the last appended row in the primary table index.


Notes

  • The administration of a unique secondary table key is updated immediately; the administration of a non-unique key is not updated until the secondary table key is next used explicitly (lazy update). Runtime costs for creating or updating a non-unique secondary table key are not incurred therefore until it is used for the first time.
  • The value operator VALUE can also be used to construct the content of internal tables.

Addition

... SORTED BY comp

Effect

Used correctly, this addition can produce ranking lists in descending order. This only works if a value greater than 0 is specified in the declaration of the internal table in the addition INITIAL SIZE. If the value 0 is specified for INITIAL SIZE, the statement APPEND has no effect when used with the addition SORTED BY.

The addition SORTED BY can be used only when a work area wa is specified and for a standard table. Also, wa must be compatible with the row type of the table. The component comp can be specified as shown in the section Specifying Components, however only a single component can be addressed using the object component selector, and no attributes of classes.

As long as the declaration of the internal table for INITIAL SIZE has a value greater than zero, the statement is executed in two steps:

  • Starting from the final row, the table is scanned for a row in which the value of the component comp is greater than or equal to the value of the component comp of wa. If such a row exists, the work area wa is inserted after this row with respect to the primary index. In no such row is found, the work area wa is inserted before the first row with respect to the primary index. The row numbers of all rows after the inserted row are increased by 1 in the primary table index.
  • If the number of rows before the statement is executed is greater than or equal to the number specified in the declaration of the internal table in the addition INITIAL SIZE, then the new final row is deleted with respect to the primary table index.

When using only the statement APPEND with addition SORTED BY to fill an internal table, this rule results in an internal table that contains no more than the number of rows specified in its definition after INITIAL SIZE and that is sorted in descending order with regard to the primary table index by component comp (ranking).

Programming Guideline

Create ranking lists with unsorted filling


Example

Creates a ranking of the three flights of a connection showing the most free seats.

PARAMETERS: p_carrid TYPE sflight-carrid, 
            p_connid TYPE sflight-connid. 

DATA: BEGIN OF seats, 
        fldate TYPE sflight-fldate, 
        seatsocc TYPE sflight-seatsocc, 
        seatsmax  TYPE sflight-seatsmax, 
        seatsfree TYPE sflight-seatsocc, 
      END OF seats. 

DATA seats_tab LIKE STANDARD TABLE OF seats 
               INITIAL SIZE 3. 

SELECT fldate, seatsocc, seatsmax 
       FROM sflight 
       WHERE carrid = @p_carrid AND 
             connid = @p_connid 
       INTO @seats. 
  seats-seatsfree = seats-seatsmax - seats-seatsocc. 
  APPEND seats TO seats_tab SORTED BY seatsfree. 
ENDSELECT.

Exceptions


Catchable Exceptions

CX_SY_ITAB_DUPLICATE_KEY

  • Cause: Duplicate key values in unique secondary key
    Runtime Error: ITAB_DUPLICATE_KEY


Non-Catchable Exceptions

  • Cause: Row with identical key inserted (target table defined using UNIQUE)
    Runtime Error: ITAB_DUPLICATE_KEY_IDX_OP
  • Cause: Sort order violated after an APPEND on a sorted table
    Runtime Error: ITAB_ILLEGAL_SORT_ORDER:
  • Cause: Invalid index value (<= 0) when FROM, TO, or INDEX specified
    Runtime Error: TABLE_INVALID_INDEX
  • Cause: Memory area violated when TABLES parameter accessed
    Runtime Error: ITAB_STRUC_ACCESS_VIOLATION

Continue

APPEND - line_spec

APPEND - result

Internal Table, Appending Rows - Example