Pretty wild stuff. This was in 11.2.0.3.9, EE…
SQL> select * from dcspp_order_rel where order_id = 'EXP1439962334' and sequence_num = 5; ORDER_ID RELATIONSHIPS SEQUENCE_NUM ---------------------------------------- ---------------------------------------- ------------ EXP1439962334 r406622317 5 SQL> select * from dcspp_order_rel where order_id = 'EXP1439962334' and sequence_num = 7; ORDER_ID RELATIONSHIPS SEQUENCE_NUM ---------------------------------------- ---------------------------------------- ------------ EXP1439962334 r406622317 5 SQL> analyze table dcspp_order_rel validate structure online; Table analyzed. SQL> analyze table dcspp_order_rel validate structure cascade online; Table analyzed. SQL> select * from dcspp_order_rel where order_id = 'EXP1439962334' and sequence_num = 5; ORDER_ID RELATIONSHIPS SEQUENCE_NUM ---------------------------------------- ---------------------------------------- ------------ EXP1439962334 r406622317 5 SQL> select * from dcspp_order_rel where order_id = 'EXP1439962334' and sequence_num = 7; ORDER_ID RELATIONSHIPS SEQUENCE_NUM ---------------------------------------- ---------------------------------------- ------------ EXP1439962334 r406622317 5 SQL> alter table dcspp_order_rel drop constraint dcspp_order_rel_p; Table altered. SQL> drop index dcspp_order_rel_p; Index dropped. SQL> create unique index atg_core_prod.dcspp_order_rel_p on dcspp_order_rel (order_id, sequence_num) 2 tablespace core_index_compressed parallel 16; Index created. SQL> alter table dcspp_order_rel add constraint dcspp_order_rel_p primary key(order_id, sequence_num) using index; Table altered. SQL> select * from dcspp_order_rel where order_id = 'EXP1439962334' and sequence_num = 7; no rows selected SQL> select * from dcspp_order_rel where order_id = 'EXP1439962334' and sequence_num = 5; EXP1439962334 r406622317 5 SQL>