Use the following statements as an example:
Create table test_items (item_id number, item_desc varchar2(20), item_attrib varchar2(100));
Alter table test_items add constraint no_double_codes unique(item_desc, item_attrib);
Use the following statements as an example:
Create table test_items (item_id number, item_desc varchar2(20), item_attrib varchar2(100));
Alter table test_items add constraint no_double_codes unique(item_desc, item_attrib);