Violate a foreign key : Create Foreign Key « Constraints « Oracle PL / SQL

1. Oracle PL / SQL
2. Constraints
3. Create Foreign Key

Violate a foreign key

  

SQL>
SQL> create table p ( pk  int primary key )
  2  /

Table created.

SQL> create table c
  2  ( fk  constraint c_fk
  3        references p(pk)
  4        deferrable
  5        initially immediate
  6  )
  7  /

Table created.

SQL> insert into p values ( 1 );

1 row created.

SQL> insert into c values ( 1 );

1 row created.

SQL>
SQL> update p set pk = 2;
update p set pk = 2
*
ERROR at line 1:
ORA-02292: integrity constraint (JAVA2S.C_FK) violated - child record found


SQL>
SQL> set constraint c_fk deferred;

Constraint set.

SQL>
SQL> update p set pk = 2;

1 row updated.

SQL>
SQL> set constraint c_fk immediate;
set constraint c_fk immediate
*
ERROR at line 1:
ORA-02291: integrity constraint (JAVA2S.C_FK) violated - parent key not found


SQL>
SQL> update c set fk = 2;

1 row updated.

SQL>
SQL> set constraint c_fk immediate;

Constraint set.

SQL>
SQL> drop table p;
drop table p
           *
ERROR at line 1:
ORA-02449: unique/primary keys in table referenced by foreign keys


SQL> drop table c;

Table dropped.

SQL>
SQL>

   
    
  

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