dependencies among object types. : Type Hierarchy « Object Oriented Database « Oracle PL / SQL






dependencies among object types.

  
SQL>
SQL> CREATE OR REPLACE TYPE Obj1 AS OBJECT (
  2    f1 NUMBER,
  3    f2 VARCHAR2(10),
  4    f3 DATE
  5  );
  6  /

Type created.

SQL> show errors
No errors.
SQL>
SQL> CREATE OR REPLACE TYPE Obj2 AS OBJECT (
  2    f1 DATE,
  3    f2 CHAR(1)
  4  );
  5  /

Type created.

SQL> show errors
No errors.
SQL>
SQL> CREATE OR REPLACE TYPE Obj3 AS OBJECT (
  2    a Obj1,
  3    b Obj2
  4  );
  5  /

Type created.

SQL> show errors
No errors.
SQL>
 This will fail, since Obj3 depends on Obj1 and Obj2
SQL> DROP TYPE Obj1;
DROP TYPE Obj1
*
ERROR at line 1:
ORA-02303: cannot drop or replace a type with type or table dependents


SQL>
 But if we drop Obj3 first:
SQL> DROP TYPE Obj3;

Type dropped.

SQL>
 Then it will succeed.
SQL> DROP TYPE Obj1;

Type dropped.

SQL>

   
  








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