unable to add foriegn key constaint

[raghunana]

hello friends,
i am a beginer.I was unable to add a foriegn key constraint to my NAMES table which refers my EMPLOYEE TABLE

SQL> desc employee
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 FNAME                                              VARCHAR2(10)
 LNAME                                              VARCHAR2(10)
 SSN                                       NOT NULL NUMBER(4)
 ADDRESS                                            VARCHAR2(50)
 SEX                                                VARCHAR2(1)
 SALARY                                             NUMBER(5)
 SUPERSSN                                           NUMBER(5)
 DNO                                                NUMBER(1)

SQL> desc names
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 NAME                                               VARCHAR2(5)
 NSSN                                               NUMBER(4)

SQL> alter table names add constraint nn8 foriegn key(nssn) references employee(ssn);
alter table names add constraint nn8 foriegn key(nssn) references employee(ssn)
                                                 *
ERROR at line 1:
ORA-01735: invalid ALTER TABLE option

[Dave44]

hello friends,
i am a beginer.I was unable to add a foriegn key constraint to my NAMES table which refers my EMPLOYEE TABLE

SQL> desc employee
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 FNAME                                              VARCHAR2(10)
 LNAME                                              VARCHAR2(10)
 SSN                                       NOT NULL NUMBER(4)
 ADDRESS                                            VARCHAR2(50)
 SEX                                                VARCHAR2(1)
 SALARY                                             NUMBER(5)
 SUPERSSN                                           NUMBER(5)
 DNO                                                NUMBER(1)

SQL> desc names
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 NAME                                               VARCHAR2(5)
 NSSN                                               NUMBER(4)

SQL> alter table names add constraint nn8 foriegn key(nssn) references employee(ssn);
alter table names add constraint nn8 foriegn key(nssn) references employee(ssn)
                                                 *
ERROR at line 1:
ORA-01735: invalid ALTER TABLE option

Just remember that a foreign key must reference either a unique key or primary key on another table. (i cant see what your indexes and primary keys are here)

**but in this case the immediate problem appears to be your spelling of the word foreign (not foriegn) ** :)

[debasisdas]

your problem is poor spelling
use FOREIGN KEY
YOUR PROBLEM WILL BE SOLVED

note:-foreign key refers to a Primary key or at least an Unique field.
Take care in future.