The ORA-00001: unique constraint (string.string) violated error comes when you try to update or insert a record in a table(Oracle Database) that creates a duplicate on the columns which are defined as unique.
As per Oracle error message guide,
ORA-00001: unique constraint (string.string) violatedCause: An UPDATE or INSERT statement attempted to insert a duplicate key. For Trusted Oracle configured in DBMS MAC mode, you may see this message if a duplicate entry exists at a different level.
Action: Either remove the unique restriction or do not insert the key.
Let’s say you have a table employee where employee_id is either a primary key or you have defined a unique constraint on it.
CREATE TABLE employee ( employe_id NUMBER PRIMARY KEY, name VARCHAR2(100) );
Note:- Oracle creates a unique constraint on the column defined as a primary key.
Insert data in this table
INSERT INTO employee VALUES (100,'Steve'); INSERT INTO employee VALUES (101, 'Thomas');
Now insert records with a duplicate value
SQL> INSERT INTO employee VALUES (100,'John'); INSERT INTO employee VALUES (100,'John') * ERROR at line 1: ORA-00001: unique constraint (APPS.SYS_C001228683) violated
Now you already have an employee steve with employee_id =100 and there is an insert or update on this table which tries to create another record with employee_id =100. This violates the unique constraint on the employee_id columns and you get,
ERROR at line 1:
ORA-00001: unique constraint (APPS.SYS_C001228683) violated
Just drop the unique constraint on columns to resolve the ORA-00001: unique constraint error in Oracle Database.