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?