Oracle Procedures

Oracle Procedures are sets of SQL statements that can be stored and executed as a single unit within the Oracle database. Procedures are commonly used to group related operations and perform complex tasks that require multiple queries, updates or calculations.

Procedures have several benefits, including:

• Reusability: Once a procedure has been created, it can be called from anywhere within the database, eliminating the need to rewrite the same code multiple times.

• Modularity: Procedures can be divided into smaller, more manageable units, making them easier to develop, test and maintain.

• Security: Procedures can be granted specific access privileges, such as execution rights, without granting direct access to underlying data.

To create a procedure, you must first define the procedure's name, parameters (if any) and code. Here's an example of a simple procedure that adds two numbers together:

CREATE OR REPLACE PROCEDURE add_numbers(
  num1 IN NUMBER,
  num2 IN NUMBER,
  result OUT NUMBER
) IS
BEGIN
  result := num1 + num2;
END;
/

In this example, the procedure is called "add_numbers" and takes two input parameters (num1 and num2) and one output parameter (result). The procedure simply adds the two input parameters together and stores the sum in the output parameter.

Once the procedure has been created, it can be executed using the SQL command "EXECUTE". Here's an example of how to call the "add_numbers" procedure:

DECLARE
  total NUMBER;
BEGIN
  add_numbers(10, 20, total);
  DBMS_OUTPUT.PUT_LINE('Total is: ' || total);
END;
/

In this example, the "DECLARE" block defines a variable called "total", which is used to store the output of the "add_numbers" procedure. The "add_numbers" procedure is called with the values 10 and 20 for the input parameters num1 and num2, respectively, and the result is stored in the "total" variable. Finally, the result is displayed using the "DBMS_OUTPUT.PUT_LINE" statement.

In conclusion, Oracle Procedures are a powerful tool for organizing and executing complex SQL operations within the database. By dividing code into modular units and granting specific access privileges, procedures can help to improve development, testing and maintenance of database applications.