我正在尝试在Oracle中创建一个对象方法,如下所示：
CREATE OR REPLACE TYPE BODY TheType AS
MEMBER FUNCTION getAtt RETURN VARCHAR2 IS
BEGIN
RETURN DEREF(SELF.Att).Att2;
END;
END;
/
但是我收到以下错误：
PLS-00306: wrong number or types of arguments in call to 'DEREF'
类型TheType也是这样声明的：
CREATE OR REPLACE TYPE TheType UNDER SuperType ();
/
...
ALTER TYPE TheType ADD ATTRIBUTE ( Att REF TheType ) CASCADE;
...
ALTER TYPE TheType
ADD MEMBER FUNCTION getAtt RETURN VARCHAR2
CASCADE;
和Supertype的定义：
CREATE OR REPLACE TYPE SuperType AS OBJECT ( Att2 VARCHAR2(50) ) NOT FINAL NOT INSTANTIABLE; /
我给DEREF函数一个具有正确类型的var,为什么会出现这个错误？
如果我信任Oracle doc,它应该工作
谢谢.
解决方法
将DEREF转换为sql.例如
sql> create or replace type supertype as object ( att2 varchar2(50) ) 2 not final not instantiable; 3 / Type created. sql> create or replace type thetype under supertype ( 2 att ref thetype,3 member function getatt return varchar2); 4 / Type created. sql> show errors type thetype No errors. sql> create or replace type body thetype as 2 member function getatt return varchar2 is 3 v_t thetype; 4 begin 5 select deref(self.att) into v_t from dual; 6 return v_t.att2; 7 end; 8 end; 9 / Type body created. sql> show errors type body thetype No errors. sql> create table thetypes of thetype; Table created. sql> insert into thetypes values ('hi there',null); 1 row created. sql> set serverout on sql> declare 2 v_t thetype; 3 begin 4 select thetype(null,ref(a)) into v_t from thetypes a; 5 dbms_output.put_line(v_t.getatt); 6 end; 7 / hi there PL/sql procedure successfully completed. sql>
