Can you explain the difference between a function and a procedure in PL/SQL, and provide an example of when you would use each one in a database application?

Explanation of the Difference Between a Function and a Procedure in PL/SQL

In PL/SQL, a function and a procedure are both subprograms that can be defined to perform specific tasks within a database application. The main difference between the two is that a function returns a single value, whereas a procedure does not return any value. Additionally, a function can be used in SQL queries, while a procedure cannot.

Example of When to Use a Function:

Let's say you have a database table that stores employee salaries, and you want to calculate the annual bonus for each employee based on their salary. In this case, you can create a function that takes the salary as input parameter and returns the calculated bonus amount. This function can then be called within SQL queries to retrieve the bonus amount for each employee.

Example of When to Use a Procedure:

Now, let's consider a scenario where you need to update the email address of all the employees in a database table based on a certain condition. In this case, you can create a procedure that accepts the condition as input parameter and updates the email addresses accordingly. Since a procedure does not return any value, it can be used to perform operations that do not require a return value.

In summary, functions are best suited for calculations and returning values, while procedures are ideal for performing operations that do not need to return a value.