Oracle9i Enterprise Edition Release 9.2.0.1.0 - Production
PL/SQL Release 9.2.0.1.0 - Production
CORE    9.2.0.1.0       Production
TNS for 32-bit Windows: Version 9.2.0.1.0 - Production
NLSRTL Version 9.2.0.1.0 - Production

SQL> create table temp(no number);

Table created.

SQL>  alter table temp add primary key(no) disable validate;

Table altered.

SQL> insert into temp values(1);
insert into temp values(1)
*
ERROR at line 1:
ORA-25128: No insert/update/delete on table with constraint (SCOTT.SYS_C003052)
disabled and validated