PL/SQL Variables and Constants

A variable in any programming language is the name of space where values are stored and controlled by our code/program

• We can not use reserve keyword as a variable name 
• Variable length should not exceed 30 characters
• The variable name consists of letters followed by other letters, dollar sign, underscore and numerals
• The variable name should be clear and easy to understand

Here we'll learn how to declare and initialize variables in PL/SQL

The basic syntax for declaring a variable in PL/SQL is following

variable_name [CONSTANT] datatype [NOT NULL] [:= | DEFAULT initial_value] 

Here variable_name is the identifier of variable and datatype is a valid PL/SQL datatype. CONSTANT and DEFAULT are keywords used to define constants and set default values of variables

PL/SQL Basic Syntax, Block Structure and Anonymous block

PL/SQL is highly structured language and it's program units are written in the block of code, In this tutorial, we'll learn about basic syntax and the block structure of PL/SQL

A piece of code that is organized in a properly defined sequence is called a Block. A PL/SQL Block consists of 3 parts

DECLARE
<<declaration >>
--Declare Variables,Constants, Cursors and all elements

BEGIN
<<executable statements>>
--SQL, PL/SQL Commands 

EXCEPTION
<<exception handling>>
--Code to handle the exception

END;

PL/SQL Tutorial - What is PL/SQL, Features and Advantages of PL/SQL

PL/SQL is developed by Oracle Corporation to increase/enhance capabilities of SQL, PL/SQL stands for Procedural Language extension to SQL . PL/SQL is highly structured and expressive language and because of its expressive syntax it is very easy to understand and learn

PL/SQL is integrated with Oracle Database and can be called from any other programming language. It is tightly integrated with SQL so it's easy to learn PL/SQL if you have knowledge of SQL