CREATE OR REPLACE PROCEDURE INSERT_EMPLOYEE(empCsv IN EMP_CSV_TABLE) AS
BEGIN
  MERGE INTO Employee pt
  USING empCsv src
  ON (pt.FIRSTNAME = src.FIRSTNAME)
 WHEN NOT MATCHED THEN INSERT 
  (pt.FIRSTNAME, pt.LASTNAME, pt.MIDDLENAME) 
  VALUES (ps.FirstName , ps.LastName , ps.MIDDLENAME);
  
  COMMIT;
END;

SQL> create or replace TYPE EMP_CSV_OBJ AS OBJECT
  2  (
  3     FirstName VARCHAR2(50),
  4     LastName VARCHAR2(50),
  5     MiddleName VARCHAR2(50)
  6  );
  7  /

Type created.

SQL> create or replace TYPE EMP_CSV_TABLE
  2  AS TABLE OF emp_csv_obj;
  3  /

Type created.

SQL> CREATE OR REPLACE PROCEDURE INSERT_EMPLOYEE(empCsv IN EMP_CSV_TABLE) AS
  2  BEGIN
  3    MERGE INTO Employees pt
  4    USING (select * from table(empCsv)) src
  5    ON (pt.FIRST_NAME = src.FIRSTNAME)
  6   WHEN NOT MATCHED THEN INSERT
  7    (pt.FIRST_NAME, pt.LAST_NAME, pt.MIDDLE_NAME)
  8    VALUES (src.FirstName , src.LastName , src.MIDDLENAME);
  9
 10  -- COMMIT;
 11  END;
 12  /

Procedure created.

CREATE OR REPLACE PROCEDURE INSERT_EMPLOYEE(empCsv IN EMP_CSV_TABLE) AS
BEGIN
  MERGE INTO Employee pt
  USING TABLE(empCsv) src
  ON (pt.FIRSTNAME = src.FIRSTNAME)
 WHEN NOT MATCHED THEN INSERT 
  (pt.FIRSTNAME, pt.LASTNAME, pt.MIDDLENAME) 
  VALUES (src.FirstName , src.LastName , src.MIDDLENAME);
END;
/