Oracle PL/SQL String 中参数名称中的参数值

Question

您好，我需要检索参数名称在不同参数中的参数值。

假设过程如下

PROCEDURE findValue
(
    p_date             IN VARCHAR2,
    p_name             IN VARCHAR2,
    p_class             IN VARCHAR2,
    p_paramname             IN VARCHAR2,
)
IS

现在假设我想将 p_paramname 作为 p_date 传递，并在 PL/SQL 块中进一步使用 p_date 参数的值，我该如何使用它？

Answer 1

如果您负担得起 PL/SQL table 输入，请尝试以下逻辑：

CREATE TYPE param_tbl_type IS TABLE OF VARCHAR2(255);

CREATE OR REPLACE FUNCTION 
    (p_param_names param_tbl_type,
     p_param_values param_tbl_type)
RETURN VARCHAR2
IS
    l_dyn_func_str VARCHAR2(4000);
    l_ret_val VARCHAR2(4000);
    vCursor integer;
    fdbk PLS_INTEGER;
BEGIN

   -- make sure you have equal number of params and currespondin values. 
   -- Index much match too. i.e. if p_param_names(0) is 'p_currency' then p_param_value(0) must be 'USD' (value of currency)
   IF p_param_names.COUNT <> p_param_values.COUNT THEN
      raise_application_error(-2000,'Incorrect number of arguments');
   END IF;

   -- use this variable to generate anonymous block code
   l_dyn_fun_str:='BEGIN :retval :=  function_tobe_called (';

   -- loop through each parameter and add to the parameter list 
   FOR i in 1..p_param_names.COUNT LOOP
      IF i=0 THEN
        l_dyn_fun_str:=l_dyn_fun_str||':'||l_param_name(i);
      ELSE
        l_dyn_fun_str:=l_dyn_fun_str||','||':'||l_param_name(i);
      END IF;
   END LOOP;

   l_dyn_fun_str:=l_dyn_fun_str||'); END;'

   -- open cursor and associate with function call string (l_dyn_fun_str)
   vCursor:=DBMS_SQL.OPEN_CURSOR;
   DBMS_SQL.PARSE(vCursor,l_dyn_fun_str);

   -- loop through parameter values and associate them with bind variables
   DBMS_SQL.BIND_VARIABLE(vCursor,':retval',l_ret_val);
   FOR j in 1..p_param_values.COUNT LOOP
      DBMS_SQL.BIND_VARIABLE(vCursor, ':'||l_param_names(j), l_param_values(j));
   END LOOP;
   -- execute function 
   fdbk := DBMS_SQL.EXECUTE (vCursor);

   -- get output of function 
   DBMS_SQL.VARIABLE_VALUE (vCursor, 'retval', l_ret_val);
   RETURN l_ret_val;


END;

注意：代码语法可能不完美，但伪代码应该仍能满足您的要求。

Answer 2

只需根据可能的参数名称检查 P_PARAMNAME 的值并相应地进行分支。例如，

CREATE OR REPLACE PROCEDURE matt_test1 (p_date        IN VARCHAR2,
                                        p_name        IN VARCHAR2,
                                        p_class       IN VARCHAR2,
                                        p_paramname   IN VARCHAR2) IS
BEGIN
  CASE p_paramname
    WHEN 'P_NAME' THEN
      DBMS_OUTPUT.put_line ('Did something with P_NAME.  Value was ' || p_name);
    WHEN 'P_DATE' THEN
      DBMS_OUTPUT.put_line ('Did something with P_DATE.  Value was ' || p_date);
    WHEN 'P_CLASS' THEN
      DBMS_OUTPUT.put_line ('Did something with P_CLASS.  Value was ' || p_class);
    ELSE
      raise_application_error (-20001, 'Invalid parameter name: ' || p_paramname);
  END CASE;
END matt_test1;


begin
  matt_test1(SYSDATE,'Fred','English 101', 'P_DATE');
  matt_test1(SYSDATE,'Fred','English 101', 'P_NAME');
  matt_test1(SYSDATE,'Fred','English 101', 'P_CLASS');
end;

输出：

Did something with P_DATE.  Value was 11-Aug-2015
Did something with P_NAME.  Value was Fred
Did something with P_CLASS.  Value was English 101

Oracle PL/SQL String 中参数名称中的参数值

Oracle PL/SQL Parameter value from parameter name in String

database

oracle

plsql

procedure