oracle - 如何访问结构并获取列列表，refcursor 的数据类型？

Question

我有一个程序可以让我得到带 refcursor 的输出，游标中的数据/结构将是动态的。每次根据输入数据类型和游标中的列数都会有所不同。那么我该如何访问这个结构并获取数据类型呢？

PROCEDURE  PROC_B ( name_     IN       VARCHAR2,
                    date_     IN       DATE,
                    code_           IN       VARCHAR2,
                    sp_name_       IN       VARCHAR2,
                    wrapper_         OUT      sys_refcursor,
                    datyapes_     OUT      VARCHAR2,
                     TS2_     OUT      VARCHAR2,
                     header_   OUT      VARCHAR2)
AS
      TS_         DATE;
BEGIN
      PROC_A (name_, date_, code_, sp_name_, wrapper_, TS_, header_);
      TS2_:= TO_CHAR(TS_, 'MM-DD-YYYY.HH24_MI');

      -- Logic should come here for below requirement 
-- Get the datatypes of variables from wrapper_ (ref cursor datatype) and send them back in datyapes_ . 
 -- Eg1 : If ref cursor returns 2 values with dataytpes VARCHAR2 & Num then o/p should be VARCHAR2|NUMBER , 
 --Eg2 : If ref cursor returns 3 values with dataytpes DATE , TIMESTAMP , VARCHAR2 then o/p should be DATE|TS|VARCHAR2

  END;**

Answer 1

您可以使用 DBMS_SQL.TO_CURSOR_NUMBER 函数将 ref 游标转换为 DBMS_SQL 游标。然后，有了游标号，您可以检查通过 DBMS_SQL 操作它。这包括能够描述它的列，如下例所示:

DECLARE
  l_rc              SYS_REFCURSOR;

  l_cursor_number   INTEGER;
  l_col_cnt         INTEGER;
  l_desc_tab        DBMS_SQL.desc_tab;
  l_col_num         INTEGER;
BEGIN
  OPEN l_rc FOR 'SELECT object_name, object_type, last_ddl_time FROM dba_objects where rownum <= 10';

  l_cursor_number   := DBMS_SQL.to_cursor_number (l_rc);

  DBMS_SQL.describe_columns (l_cursor_number, l_col_cnt, l_desc_tab);

  l_col_num         := l_desc_tab.FIRST;

  IF (l_col_num IS NOT NULL) THEN
    LOOP
      DBMS_OUTPUT.put_line ('Column #' || l_col_num);
      DBMS_OUTPUT.put_line ('...name: ' || l_desc_tab (l_col_num).col_name);
      DBMS_OUTPUT.put_line ('...type: ' || l_desc_tab (l_col_num).col_type);
      DBMS_OUTPUT.put_line ('...maxlen: ' || l_desc_tab (l_col_num).col_max_len);
      -- ... other fields available in l_desc_tab(l_col_num) too.
      l_col_num   := l_desc_tab.NEXT (l_col_num);
      EXIT WHEN (l_col_num IS NULL);
    END LOOP;
  END IF;

  DBMS_SQL.close_cursor (l_cursor_number);
END;

输出

Column #1
...name: OBJECT_NAME
...type: 1
...maxlen: 128
Column #2
...name: OBJECT_TYPE
...type: 1
...maxlen: 23
Column #3
...name: LAST_DDL_TIME
...type: 12
...maxlen: 7