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我有一些表，需要在它们之上创建对象视图。

CREATE TABLE Person (
Nr NUMBER(4) PRIMARY KEY,
Name VARCHAR2(15)); 

CREATE TABLE Professor (
Nr NUMBER(4) PRIMARY KEY,
HabilThema VARCHAR2(30));

我还创建了类型：

CREATE OR REPLACE TYPE Person_Typ AS OBJECT(
    Nr INTEGER,
    Name VARCHAR2(15)
);

CREATE OR REPLACE TYPE Professor_Typ AS OBJECT(
    Nr INTEGER,
    Habilthema VARCHAR2(30),
    Person REF Person_Typ
);

如您所见，教授行对人员行有引用。现在教授的观点也应该包括人的栏目。就像是：

CREATE VIEW People OF Person_Typ
    WITH OBJECT IDENTIFIER(Nr) AS
        SELECT p.Nr, p.Name FROM Person p;

CREATE VIEW Professors OF Professor_Typ
    WITH OBJECT IDENTIFIER(Nr) AS 
        SELECT p.Nr, p.Habilthema, p.Person.Name, MAKE_REF(People,p.Nr) FROM Professor p;
                                             ^
                                             |_ Name of professor from Person table

但这不起作用：

"P"."PERSON"."NAME" invalid identifier

这甚至可以通过对象视图来实现吗？如何？

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