A foreign key to reference itself : FOREIGN KEY « Table « Oracle PL/SQL Tutorial






  1. Oracle PL/SQL Tutorial
  2. Table
  3. FOREIGN KEY
SQL>
SQL> create table employees
  2  ( empno      NUMBER(4)    constraint E_PK
  3                            primary key
  4                            constraint E_EMPNO_CHK
  5                            check (empno > 7000)
  6  , mgr        NUMBER(4)    constraint E_MGR_FK
  7                            references employees) ;

Table created.

SQL>
SQL> drop table employees;

Table dropped.








6.16.FOREIGN KEY
6.16.1.Adding a FOREIGN KEY Constraint
6.16.2.ON DELETE CASCADE clause with a FOREIGN KEY constraint
6.16.3.Use the ON DELETE SET NULL clause with a FOREIGN KEY constraint
6.16.4.ORA-02298: cannot validate (JAVA2S.PRODUCT_ORDER_FK_PRODUCT) - parent keys not found
6.16.5.A foreign key to reference itself
6.16.6.ORA-02270: no matching unique or primary key for this column-list
6.16.7.Add constraint foreign key references
6.16.8.Violate a foreign key
6.16.9.Disable foreign key
6.16.10.Many to many using a primary-key and foreign-key relationship