Database 初始化对象类型构造函数oracle

我正在用oracle开发一个数据库。 我已经创建了一个超类型，即answer和一个子类型closed\u answer。我添加了一个字段“type”来区分它们，但我希望该字段在构造函数中初始化，以便在表中插入元组时不插入该字段。我已经尝试过了，但是当我在表中插入元组时，我必须指定类型，但我不应该这样做。我错在哪里

create type answertyp as object(

id integer,

text varchar2(50),

type varchar2(25),

constructor function answertyp(self in out nocopy answertyp, text varchar2) return self as result) not final;

create type body answertyp is

constructor function answertyp(self in out nocopy answertyp, text varchar2) return self as result is

begin

self.text := text;

self.type:= 'answer';

return;

end;

end;
/

create type closed_answertyp under closed_answer(

constructor function closed_answertyp(self in out nocopy closed_answertyp, text varchar2) return self as result
) final;

create type body closed_answertyp is

constructor function closed_answertyp (self in out nocopy closed_answertyp, text varchar2) return self as result is

begin

self.text := text;

self.type := 'closed_answer';

return;

end;

end;

现在，如果我尝试这个查询，它会说参数的数量是错误的。有什么帮助吗？谢谢

insert into answer select closed_answertyp(1, 'ten') from dual;

---

SQL语句中的参数与构造函数中的参数不匹配

将

id

添加到构造函数：

constructor function closed_answertyp (self in out nocopy closed_answertyp, id integer, text varchar2) return self as result is

或者从SQL语句中删除

id

：

insert into answer select closed_answertyp('ten') from dual;