[Newbie] Basic nested table creation

Question

Hi there.
I've got a basic scheme here. First, I've got a type called Student, with various attributes. I've also got a type Degree, which holds a nested table of Students. I'm trying to implement it like this:
CREATE OR REPLACE TYPE Student_type AS OBJECT(
Name VARCHAR2(20),
Degree REF Degree_type
CREARE OR REPLACE TYPE Students_NT AS TABLE OF Student_type;
CREATE OR REPLACE TYPE Degree_type AS OBJECT(
Name VARCHAR2(20),
Students Student_NT
Looks like there's a circular dependency here, how can I solve it? I've thought I tried adding the attributes of the relation (the reference in Student_type and the nested table in the Degree_type) afterwards by altering the types, but it does not work.
What can I do? Thanks in advance.

Answer 1

Hi,
You need to create DEGREE_TYPE as an incomplete type first, as explained in the documentation :
http://download.oracle.com/docs/cd/B19306_01/appdev.102/b14260/adobjmng.htm#ADOBJ00402
So in your case :
CREATE TYPE Degree_type;
CREATE OR REPLACE TYPE Student_type AS OBJECT(
Name VARCHAR2(20),
Degree REF Degree_type
CREATE OR REPLACE TYPE Students_NT AS TABLE OF Student_type;
CREATE OR REPLACE TYPE Degree_type AS OBJECT(
Name VARCHAR2(20),
Students Students_NT
/