Question

I’m trying to make a Procedure that will duplicate multiple rows of a table (or only one single row) and incrementing the ID for each row insertion.

My problem is that inside my procedure I used a cursor to select the rows to duplicate, when i select all rows without WHERE condition in that cursor everything works fine.
But when i set a WHERE condition to select only one row… nothing happens

Here is my procedure

CREATE OR REPLACE PROCEDURE DuplicateEmployee (p_EmployeeID IN Employee.id%TYPE)
 AS
  p_New_EmployeeID Employee.id%TYPE;
  CURSOR c_DuplicateEmployee IS
    SELECT *
        FROM Employee
        WHERE Employee.id = p_EmployeeID; -- if this line is deleted all content is duplicated
  row_Employee c_DuplicateEmployee%ROWTYPE;
    BEGIN
      FOR myEmployee IN c_DuplicateEmployee LOOP
          p_New_EmployeeID := employee_seq.NEXTVAL;
          INSERT INTO Employee(id, first_name, last_name, start_date, end_date, salary, city, description)
            VALUES(p_New_EmployeeID, myEmployee.first_name, myEmployee.last_name, myEmployee.start_date, myEmployee.end_date, myEmployee.salary, myEmployee.city, myEmployee.description);
      END LOOP;
    COMMIT;
   END DuplicateEmployee;

I know in this example having a procedure selecting a primary key to duplicate is pointless but in my production base it will be used to select a Foreign key.

Bellow is the code require to create a the test table and SEQUENCE I used for this procedure

CREATE TABLE Employee
  (
    ID         VARCHAR2(4 BYTE) NOT NULL,
    First_Name VARCHAR2(10 BYTE),
    Last_Name  VARCHAR2(10 BYTE),
    Start_Date DATE,
    End_Date DATE,
    Salary      NUMBER(8,2),
    City        VARCHAR2(10 BYTE),
    Description VARCHAR2(15 BYTE)
  );
INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
  VALUES
    ('01', 'Jason', 'Martin', to_date('19960725','YYYYMMDD'), to_date('20060725','YYYYMMDD'), 1234.56, 'Toronto', 'Programmer');
INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
  VALUES
    ('02', 'Alison', 'Mathews', to_date('19760321','YYYYMMDD'), to_date('19860221','YYYYMMDD'), 6661.78, 'Vancouver', 'Tester');
INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
  VALUES
    ('03', 'James', 'Smith', to_date('19781212','YYYYMMDD'), to_date('19900315','YYYYMMDD'), 6544.78, 'Vancouver', 'Tester');
INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
  VALUES
    ('04', 'Celia', 'Rice', to_date('19821024','YYYYMMDD'), to_date('19990421','YYYYMMDD'), 2344.78, 'Vancouver', 'Manager');
INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
  VALUES
    ('05', 'Robert', 'Black', to_date('19840115','YYYYMMDD'), to_date('19980808','YYYYMMDD'), 2334.78, 'Vancouver', 'Tester');
 INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
  VALUES
    ('06', 'Linda', 'Green', to_date('19870730','YYYYMMDD'), to_date('19960104','YYYYMMDD'), 4322.78, 'New York', 'Tester');
INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
VALUES
    ('07', 'David', 'Larry', to_date('19901231','YYYYMMDD'), to_date('19980212','YYYYMMDD'), 7897.78, 'New York', 'Manager');
INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
VALUES
    ('08', 'James', 'Cat', to_date('19960917','YYYYMMDD'), to_date('20020415','YYYYMMDD'), 1232.78, 'Vancouver', 'Tester');

Here for the Sequence that will manage Primary key (ID)

CREATE SEQUENCE "TEST"."EMPLOYEE_SEQ" MINVALUE 1 MAXVALUE 999999999999999999999999999 INCREMENT BY 1 START WITH 1 NOCACHE ORDER NOCYCLE ;

And here the code to execute the procedure

BEGIN
  employeepackage.duplicateemployee(5);
END;

I really don’t understand why it doesn’t properly work for a single row when it’s working to plicate all rows ? It there a limitation for cursors having less than 2 rows ?

Any help would be much appreciated 😉

Answer 1

Why do you need a cursor? You can do this with SQL directly:

INSERT INTO Employee(id, first_name, last_name, 
                     start_date, end_date, 
                     salary, city, description)
SELECT employee_seq.NEXTVAL, e.first_name, e.last_name,
       e.start_date, e.end_date, 
       e.salary, e.city, e.description
FROM Employee e
WHERE e.id = p_EmployeeID;

Anyway, the actual problem is that your ID is a VARCHAR2(4), whereas you think it is a NUMBER. You actually do not have an employee with ID = 5, but you do have one with ID = '05'. So without changing anything, your procedure already works:

BEGIN
  employeepackage.duplicateemployee('05');
END;

Of course, it would make sense to change the data type of ID.