oracle - 带游标参数的管道函数 oracle

Question

例如，如果我有这种功能

function test_pipe(p_source in t_cursor)
return t_tab
pipelined
as --some code goes here

t_cursor 是引用光标。我知道我可以像

那样调用这个函数

select * from table(test_pipe(cursor(select 1 from dual)));

但是如果我在包中声明游标并希望将其作为参数传递，该怎么办？像这样的东西。

procedure test is
v_ct pls_integer;
cursor main_cur is select 1 from dual;
begin
select count(*) into v_ct from table(test_pipe(main_cur));
--some code
end;

我收到 main_cur 无效标识符 - pl/sql:ORA00904 错误。我应该如何编码才能将 main_cur 作为参数传递给 test_pipe？

Answer 1

cursor main_cur is select 1 from dual;

游标是用于从结果集中获取行的指针。

因此，当您执行table(test_pipe(main_cur))时，您并没有将行源传递给管道函数。您需要首先获取行，然后传递行源。

测试用例:

SQL> CREATE or replace TYPE target_table_row
  2  AS
  3    OBJECT
  4    ( EMPNO NUMBER(4) ,
  5      ENAME VARCHAR2(10)
  6      )
  7  /

Type created.

SQL>
SQL> sho err
No errors.
SQL>
SQL> CREATE or replace TYPE target_table_rows
  2  AS
  3    TABLE OF target_table_row;
  4  /

Type created.

SQL>
SQL> sho err
No errors.
SQL>

管道函数

SQL> CREATE OR REPLACE FUNCTION pipelined_fx(
  2      p_cursor IN SYS_REFCURSOR)
  3    RETURN target_table_rows PIPELINED PARALLEL_ENABLE(
  4      PARTITION p_cursor BY ANY)
  5  IS
  6  TYPE cursor_ntt
  7  IS
  8    TABLE OF emp%ROWTYPE;
  9    nt_src_data cursor_ntt;
 10  BEGIN
 11    LOOP
 12      FETCH p_cursor BULK COLLECT INTO nt_src_data LIMIT 100;
 13      FOR i IN 1 .. nt_src_data.COUNT
 14      LOOP
 15        PIPE ROW (target_table_row( nt_src_data(i).empno, nt_src_data(i).ename ));
 16      END LOOP;
 17      EXIT
 18    WHEN p_cursor%NOTFOUND;
 19    END LOOP;
 20    CLOSE p_cursor;
 21    RETURN;
 22  END pipelined_fx;
 23  /

Function created.

SQL>
SQL> show errors
No errors.
SQL>

现在，让我们测试一下管道函数:

SQL> DECLARE
  2    rc SYS_REFCURSOR;
  3    num NUMBER;
  4  BEGIN
  5    OPEN RC FOR SELECT * FROM emp;
  6    SELECT count(*) INTO num FROM TABLE(pipelined_fx(rc));
  7    DBMS_OUTPUT.PUT_LINE( num || ' rows in total.' );
  8  END;
  9  /
14 rows in total.

PL/SQL procedure successfully completed.

SQL>