How do I fetch values from a DBMS_SQL cursor derived from a SYS_REFCURSOR?

问题

I'm trying to iterate over a cursor number from DBMS_SQL.TO_CURSOR_NUMBER, and running into problems – when I try to pull a value into a variable, I get ORA-01007 (variable not in select list).

Here's a code block that replicates my problem:

DECLARE
  cur SYS_REFCURSOR;
  nm INTEGER;
  colDescs DBMS_SQL.DESC_TAB2;
  numCols INTEGER;
  val VARCHAR2(3);
BEGIN
  OPEN cur FOR
    SELECT 'x' AS foo, 2 AS bar
    FROM dual;
  nm := DBMS_SQL.TO_CURSOR_NUMBER(cur);
  DBMS_SQL.DESCRIBE_COLUMNS2(nm, numCols, colDescs);

  DBMS_OUTPUT.PUT_LINE(numCols);

  DBMS_OUTPUT.PUT_LINE(DBMS_SQL.FETCH_ROWS(nm));

  DBMS_SQL.column_value(nm, 1, val);
  DBMS_OUTPUT.PUT_LINE(val);

  DBMS_SQL.CLOSE_CURSOR(nm);
EXCEPTION
  WHEN OTHERS THEN
    DBMS_SQL.CLOSE_CURSOR(nm);
    DBMS_OUTPUT.PUT_LINE('borked '||SQLCODE);
END;
/

Expected output:

2
1
x

Actual output:

2
1
borked -1007

回答1:

You haven't done the DEFINE_COLUMN step(s); before you fetch:

  DBMS_SQL.DEFINE_COLUMN(nm, 1, val, 3);

So this works:

DECLARE
  cur SYS_REFCURSOR;
  nm INTEGER;
  colDescs DBMS_SQL.DESC_TAB2;
  numCols INTEGER;
  val VARCHAR2(3);
BEGIN
  OPEN cur FOR
    SELECT 'x' AS foo, 2 AS bar
    FROM dual;
  nm := DBMS_SQL.TO_CURSOR_NUMBER(cur);
  DBMS_SQL.DESCRIBE_COLUMNS2(nm, numCols, colDescs);

  DBMS_OUTPUT.PUT_LINE(numCols);

  DBMS_SQL.DEFINE_COLUMN(nm, 1, val, 3);

  DBMS_OUTPUT.PUT_LINE(DBMS_SQL.FETCH_ROWS(nm));

  DBMS_SQL.column_value(nm, 1, val);
  DBMS_OUTPUT.PUT_LINE(val);

  DBMS_SQL.CLOSE_CURSOR(nm);
EXCEPTION
  WHEN OTHERS THEN
    DBMS_SQL.CLOSE_CURSOR(nm);
    DBMS_OUTPUT.PUT_LINE('borked '||SQLERRM);
    DBMS_OUTPUT.PUT_LINE(DBMS_UTILITY.FORMAT_ERROR_BACKTRACE);
END;
/

anonymous block completed
2
1
x

来源：https://stackoverflow.com/questions/26242308/how-do-i-fetch-values-from-a-dbms-sql-cursor-derived-from-a-sys-refcursor

标签

Oracle

oracle11g