Oracle remove unique constraint

a grammar

DISABLE|ENABLE CONSTRAINT constraint_name

two code

1. SQL>select constraint_name,constraint_type,status from user_constraints
2. 2where table_name ='USERINFO_U2';
4. CONSTRAINT_NAME C STATUS
5. ---------------------------------------
6. SYS_C0011117 P ENABLED
7. UN_USERNAME_NEW U ENABLED
9. SQL> alter table userinfo_u2
10. 2 disable constraint UN_USERNAME_NEW;
12. 表已更改。
14. SQL>select constraint_name,constraint_type,status from user_constraints
15. 2where table_name ='USERINFO_U2';
17. CONSTRAINT_NAME C STATUS
18. ---------------------------------------
19. SYS_C0011117 P ENABLED
20. UN_USERNAME_NEW U DISABLED

trigram

DROP CONSTRAINT constraint_name

four code

1. SQL> alter table userinfo_u2
2. 2 drop constraint UN_USERNAME_NEW;
4. 表已更改。