嵌套表的引用问题
一下SQL在执行到最后一句时报错

CREATE   TYPE   TEACHER   AS   OBJECT
(
    NAME   VARCHAR2(105),
    BIRTH   DATE
);
/

CREATE   TYPE   TEACHER_TABLE   AS   TABLE   OF   TEACHER;
/

CREATE   TABLE   CENTER(
    NAME   VARCHAR2(4)   PRIMARY   KEY,
    TEACHERS   TEACHER_TABLE
)NESTED   TABLE   TEACHERS   STORE   AS   TEACHER_TABLE_CENTER;

INSERT   INTO   CENTER   VALUES( '徐汇 ',
    TEACHER_TABLE(
        TEACHER( '张老师 ',   to_date( '1980-1-1 ',   'yyyy-mm-dd ')),
        TEACHER( '李老师 ',   to_date( '1982-1-1 ',   'yyyy-mm-dd ')),
        TEACHER( '胡老师 ',   to_date( '1978-1-1 ',   'yyyy-mm-dd '))
    )
);

INSERT   INTO   CENTER   VALUES( '长宁 ',
    TEACHER_TABLE(
        TEACHER( '方方老师 ',   to_date( '1981-12-31 ',   'yyyy-mm-dd ')),
        TEACHER( '马老师 ',   to_date( '1983-12-31 ',   'yyyy-mm-dd '))
    )
);

CREATE   TYPE   STUDENT   AS   OBJECT
(
    NAME   VARCHAR2(105),
    STUDNO   CHAR(10)
);
/

CREATE   TYPE   STUDENT_ARR   AS   VARRAY(30)   OF   STUDENT;
/

CREATE   TABLE   CLASS(
    CLASSID   VARCHAR2(7)   PRIMARY   KEY,
    CENTER_NAME   VARCHAR2(4)   REFERENCES   CENTER(NAME),
    TEACHER_REF   REF   TEACHER,
    STUDENTS   STUDENT_ARR
);

INSERT   INTO   CLASS
SELECT   '0722T03 ',   '徐汇 ',   REF(VALUE(T)),
STUDENT_ARR(
STUDENT( '张三 ',   '0001155245 '),
STUDENT( '李四 ',   '0001152444 '),
STUDENT( '王五 ',   '0001155242 '),
STUDENT( '赵六 ',   '0001158357 ')
)
FROM   TABLE(SELECT   TEACHERS   FROM   CENTER   WHERE   NAME   =   '徐汇 ')   T
WHERE   NAME   =   '张老师 ';

表结构简单来说就时有个CENTER表中有个个TEACHER的嵌套表，CLASS表中的TEACHER_REF字段希望引用该TEACHER嵌套表中的某记录，但在最后实行插入是报缺少右括号，但我实在找不出什么地方缺右括号啊。

------解决方案--------------------
帮顶
------解决方案--------------------
调试了一下,感觉是 REF(VALUE(T)) 错,
不知道其中的VALUE(T)能不能这样用的?
------解决方案--------------------
参考


REF函数用于对象表的创建和插入，看下面的例子：

--创建表对象Address_TP
CREATE TYPE Address_TP AS OBJECT (
address_id number,
street VARCHAR2(40),
building VARCHAR2(40),
phone VARCHAR2(15)
);
--创建表对象Student_TP
CREATE TYPE Student_TP AS OBJECT (
Name VARCHAR2(15),
Age NUMBER,
Address REF Address_TP
);
--创建对象表Address
CREATE TABLE Address OF Address_TP (
PRIMARY KEY (address_id)
);
--创建对象表Student
CREATE TABLE Student OF Student_TP (
PRIMARY KEY (Name)
);

--插入数据
INSERT INTO Address VALUES (
1, 'BeijingJianGuoMenWaiDaJie ', 'Buiding-A ',