This Posts Presents SQL Statement to Alter A Oracle DB (12c) TableTo Add Unique Constraint For Unique Rows Where Primary Keys or Unique Column Constraints Are Not There.
If Oracle DB Table Have A,B,C,D,E,F fields , then Add A Constraint On All Fields Of This Table
ALTER TABLE DUPLICATE_TEST ADD CONSTRAINT DUPLICATE_TEST_CONSTRAINT UNIQUE (A,B,C,D,E,F)
On Entering To Duplicate Row It Will Return Below Error :
[23000][1] ORA-00001: unique constraint (DB_NAME.Table_Name) violated
Reference :
SQL Query To Find Duplicate Rows In A Oracle DB Table
https://esumit.blog/2017/10/25/sql-query-to-find-duplicate-rows-in-a-oracle-database-table/
Sumit Arora 