PL/SQL Variables

These are placeholders that store the values that can change through the PL/SQL Block.

The General Syntax to declare a variable is:

Variable_name datatype [NOT NULL: = value];
• variable_name is the name of the variable.
• datatype is a valid PL/SQL datatype.
• NOT NULL is an optional specification on the variable.
• value or DEFAULT valueis also an optional specification, where you can initialize a variable.
• Each variable declaration is a separate statement and must be terminated by a semicolon.

For example, if you want to store the current salary of an employee, you can use a variable.
DECLARE
salary number (6);

* “salary” is a variable of datatype number and of length 6.

When a variable is specified as NOT NULL, you must initialize the variable when it is declared.

For example: The below example declares two variables, one of which is a not null.
DECLARE
salary number(4);
dept varchar2(10) NOT NULL := “HR Dept”;
The value of a variable can change in the execution or exception section of the PL/SQL Block. We can assign values to variables in the two ways given below.

1) We can directly assign values to variables.
The General Syntax is:
variable_name:= value;

2) We can assign values to variables directly from the database columns by using a SELECT... INTO statement. The General Syntax is:

SELECT column_name

INTO variable_name

FROM table_name

[WHERE condition];

Example: The below program will get the salary of an employee with id '1116' and display it on the screen.
DECLARE
var_salary number(6);
var_emp_id number(6) = 1116;
BEGIN
SELECT salary
INTO var_salary
FROM employee
WHERE emp_id = var_emp_id;
dbms_output.put_line(var_salary);
dbms_output.put_line('The employee '
|| var_emp_id || ' has salary ' || var_salary);
END;
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