如何访问结构并获取列列表，refcursor 的数据类型？

Question

我有一个程序可以使用 refcursor 获取输出，而 data/structure 中的光标将是动态的。每次根据输入数据类型和游标中的列数都会有所不同。那么如何访问此结构并获取数据类型？

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

由于您使用的是 11g，因此可以使用 the dbms_sql package to interrogate your ref cursor, and then loop over the column types. They are reported as numbers so you'll need to translate the type numbers to strings (listed here)。

这是一个给你思路的演示：

set serveroutput on
DECLARE
  -- mimicking your procedure arguments
  wrapper_ SYS_REFCURSOR;
  datyapes_ VARCHAR(100);

  L_COLS NUMBER;
  L_DESC DBMS_SQL.DESC_TAB;
  L_CURS INTEGER;
  L_VARCHAR VARCHAR2(4000);
BEGIN
  -- fake cursor, instead of procedure call
  open wrapper_ for q'[select 42, 'Test', date '2017-03-02' from dual]';

  L_CURS := DBMS_SQL.TO_CURSOR_NUMBER(wrapper_);
  DBMS_SQL.DESCRIBE_COLUMNS(C => L_CURS, COL_CNT => L_COLS,
    DESC_T => L_DESC);

  FOR i IN 1..L_COLS LOOP
    datyapes_ := datyapes_ || CASE WHEN i > 1 THEN '|' END
      || CASE L_DESC(i).col_type
        WHEN 1 THEN 'VARCHAR2'
        WHEN 2 THEN 'NUMBER'
        WHEN 12 THEN 'DATE'
        WHEN 96 THEN 'CHAR'
        WHEN 180 THEN 'TS'
        -- more types as needed
        ELSE 'unknown'
      END;
  END LOOP;

  DBMS_SQL.CLOSE_CURSOR(L_CURS);

  -- just for debug
  dbms_output.put_line('datyapes_: ' || datyapes_);
END;
/

得到输出：

datyapes_: NUMBER|CHAR|DATE

PL/SQL procedure successfully completed.

如问题所示，我将您的变量名称保留为 datyapes_，但也许您真的有 datatypes_.

Answer 2

您可以使用 DBMS_SQL.TO_CURSOR_NUMBER 函数将引用光标转换为 DBMS_SQL 光标。然后，有了光标编号，您可以通过 DBMS_SQL 检查操作它。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

如何访问结构并获取列列表，refcursor 的数据类型？

How to access the structure and get the column list ,datatypes of refcursor?

oracle

oracle11g

cursor

sys-refcursor

ref-cursor

输出