novalidate does not work. i tried as follows :

SQL> create table aa (code char(2) constraint pk_1 primary key,name char

Table created.

SQL> insert into aa values('11','anuj1') ;

1 row created.

SQL> commit ;

Commit complete.

SQL> insert into aa values('11','anuj2') ;
insert into aa values('11','anuj2')
*
ERROR at line 1:
ORA-00001: unique constraint (SCOTT.PK_1) violated


SQL> alter table aa drop constraint pk_1 ;

Table altered.

SQL> insert into aa values('11','anuj2') ;

1 row created.

SQL> commit ;

Commit complete.

1 alter table aa add constraint
2* pk_1 primary key (code) novalidate
SQL> /
alter table aa add constraint
*
ERROR at line 1:
ORA-02437: cannot validate (SCOTT.PK_1) - primary key violated