Explain the difference between a function and a procedure in PL/SQL and provide examples of when you would use each in a database application.

2 Answers
Answered by suresh

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Focus keyword: PL/SQL function vs procedure

In PL/SQL, a function and a procedure are both database program units that can be used to perform specific tasks, but they have some key differences:

  • PL/SQL Function: A function is a type of program unit that returns a single value. It can be used to perform a specific operation and return a result to the calling program. Functions are mainly used for computations and return values based on input parameters.
  • Example of using a PL/SQL function: A function can be created to calculate the total sales amount based on the quantity and price of items sold.
  • PL/SQL Procedure: A procedure is a program unit that performs a specific task or set of tasks. Unlike functions, procedures do not return any value. They are typically used for performing operations that do not require a return value.
  • Example of using a PL/SQL procedure: A procedure can be created to update the inventory levels of products in a database after a purchase is made, without needing to return a value.

Overall, functions are ideal for calculations and returning values, while procedures are suitable for performing tasks that do not require a return value in a database application.

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Answered by suresh

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PL/SQL Interview Question: Function vs Procedure

PL/SQL Interview Question: Function vs Procedure

Functions and procedures are two important elements in PL/SQL that serve different purposes in database applications:

Function:

A function is a subprogram that returns a value. It can be used to perform a specific task and return a single value back to the calling program.

Example:

CREATE OR REPLACE FUNCTION calculate_total_price (quantity IN NUMBER, unit_price IN NUMBER) RETURN NUMBER
IS
    total_price NUMBER;
BEGIN
    total_price := quantity * unit_price;
    RETURN total_price;
END;

Functions are often used to perform calculations or data manipulations and return a result that can be used in other parts of the application.

Procedure:

A procedure is a subprogram that performs a set of actions without returning a value. It can contain multiple statements and can be used to execute tasks or operations on the database.

Example:

CREATE OR REPLACE PROCEDURE update_employee_salary (employee_id IN NUMBER, new_salary IN NUMBER)
IS
BEGIN
    UPDATE employees
    SET salary = new_salary
    WHERE employee_id = employee_id;
END;

Procedures are commonly used to modify data in the database, handle complex business logic, or perform administrative tasks.

Choosing between a function and a procedure depends on the specific requirements of the application. Functions are useful when a return value is needed for further processing, while procedures are more suitable for tasks that do not require a return value but involve multiple actions.

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Answer for Question: Explain the difference between a function and a procedure in PL/SQL and provide examples of when you would use each in a database application.