Can you explain the differences between a cursor and a ref cursor in PL/SQL, and provide an example of when you would use each one?

Sure!

In PL/SQL, a cursor is a database object that allows you to retrieve and process multiple rows of data one by one. On the other hand, a ref cursor (or reference cursor) is a data type in PL/SQL that allows you to point to the result set of a query or stored procedure, without storing the actual query results.

The main difference between a cursor and a ref cursor is that a cursor is explicitly defined using the `CURSOR` keyword within the PL/SQL code, while a ref cursor is a more dynamic and flexible way to work with query results.

When to use a cursor:
A cursor is typically used when you need to process a result set row by row, for example, looping through and performing calculations or manipulations on each row of data.

Example of using a cursor:
```sql
DECLARE
CURSOR employee_cur IS
SELECT employee_id, employee_name FROM employees;
BEGIN
FOR emp_rec IN employee_cur LOOP
-- Process each employee record here
END LOOP;
END;
```

When to use a ref cursor:
A ref cursor is beneficial when you need to pass the result set of a query or stored procedure to another program or procedure for further processing.

Example of using a ref cursor:
```sql
CREATE OR REPLACE PROCEDURE getEmployeeList(emp_cur OUT SYS_REFCURSOR) AS
BEGIN
OPEN emp_cur FOR
SELECT employee_id, employee_name FROM employees;
END;
```

In summary, understanding the differences between a cursor and a ref cursor in PL/SQL is crucial for efficient data manipulation and retrieval, and choosing the appropriate method depends on the specific requirements of your application.

[Focus keyword: cursor vs ref cursor in PL/SQL]