What is the Extract statement? Please give me some sample code.?

Question

What is the Extract statement? Please give me some sample code.?

Answer 1

Hello ,
Once you have declared the possible record types as field groups and defined their structure, you can fill the extract dataset using the following statements: EXTRACT . When the first EXTRACT statement occurs in a program, the system creates the extract dataset and adds the first extract record to it. In each subsequent EXTRACT statement, the new extract record is added to the dataset EXTRACT HEADER. When you extract the data, the record is filled with the current values of the corresponding fields. As soon as the system has processed the first EXTRACT statement for a field group , the structure of the corresponding extract record in the extract dataset is fixed. You can no longer insert new fields into the field groups and HEADER. If you try to modify one of the field groups afterwards and use it in another EXTRACT statement, a runtime error occurs. By processing EXTRACT statements several times using different field groups, you fill the extract dataset with records of different length and structure. Since you can modify field groups dynamically up to their first usage in an EXTRACT statement, extract datasets provide the advantage that you need not determine the structure at the beginning of the program.
Sample program:
REPORT  ZSPFLI  LINE-SIZE 132 LINE-COUNT 65(3)
                                             NO STANDARD PAGE HEADING.
TABLES:SPFLI,SCARR, SFLIGHT, SBOOK.
SELECT-OPTIONS: MYCARRID FOR SPFLI-CARRID.
FIELD-GROUPS: HEADER, SPFLI_FG, SFLIGHT_FG, SBOOK_FG.
INSERT:
        SPFLI-CARRID
        SPFLI-CONNID
        SFLIGHT-FLDATE
        SBOOK-BOOKID
       INTO HEADER,
        SPFLI-CARRID
        SPFLI-CONNID
        SPFLI-CITYFROM
        SPFLI-AIRPFROM
        SPFLI-CITYTO
        SPFLI-AIRPTO
        SPFLI-DEPTIME
        SCARR-CARRNAME
      INTO SPFLI_FG,
        SFLIGHT-FLDATE
        SFLIGHT-SEATSMAX
        SFLIGHT-SEATSOCC
        SFLIGHT-PRICE
      INTO SFLIGHT_FG,
        SBOOK-BOOKID
        SBOOK-CUSTOMID
        SBOOK-CUSTTYPE
        SBOOK-SMOKER
       INTO SBOOK_FG.
SELECT * FROM SPFLI WHERE CARRID IN MYCARRID.
  SELECT SINGLE * FROM SCARR WHERE CARRID = SPFLI-CARRID.
  EXTRACT SPFLI_FG.
  SELECT * FROM SFLIGHT
   WHERE CARRID = SPFLI-CARRID AND  CONNID = SPFLI-CONNID.
    EXTRACT SFLIGHT_FG.
    SELECT * FROM SBOOK
           WHERE CARRID = SFLIGHT-CARRID AND
           CONNID = SFLIGHT-CONNID AND FLDATE = SFLIGHT-FLDATE.
      EXTRACT SBOOK_FG.
      CLEAR SBOOK.
    ENDSELECT.
    CLEAR SFLIGHT.
  ENDSELECT.
  CLEAR SPFLI.
ENDSELECT.
SORT.
LOOP.
  AT SPFLI_FG.
    FORMAT COLOR COL_HEADING.
    WRITE: / SCARR-CARRNAME,
             SPFLI-CONNID, SPFLI-CITYFROM,
             SPFLI-AIRPFROM, SPFLI-CITYTO, SPFLI-AIRPTO, SPFLI-DEPTIME.
    FORMAT COLOR OFF.
  ENDAT.
  AT SFLIGHT_FG.
    WRITE: /15 SFLIGHT-FLDATE, SFLIGHT-PRICE, SFLIGHT-SEATSMAX,
               SFLIGHT-SEATSOCC.
  ENDAT.
  AT SBOOK_FG.
    WRITE: /30 SBOOK-BOOKID, SBOOK-CUSTOMID,
                 SBOOK-CUSTTYPE, SBOOK-SMOKER.
  ENDAT.
ENDLOOP.