PL/SQL - Constants and Literals
In this chapter, we will discuss constants and literals in PL/SQL. A constant holds
a value that once declared, does not change in the program. A constant declaration
specifies its name, data type, and value, and allocates storage for it. The
declaration can also impose the NOT NULL constraint.
Declaring a Constant
A constant is declared using the CONSTANT keyword. It requires an initial value
and does not allow that value to be changed. For example −
PI CONSTANT NUMBER := 3.141592654;
DECLARE
-- constant declaration
pi constant number := 3.141592654;
-- other declarations
radius number(5,2);
dia number(5,2);
circumference number(7, 2);
area number (10, 2);
BEGIN
-- processing
radius := 9.5;
dia := radius * 2;
circumference := 2.0 * pi * radius;
area := pi * radius * radius;
-- output
dbms_output.put_line('Radius: ' || radius);
dbms_output.put_line('Diameter: ' || dia);
dbms_output.put_line('Circumference: ' || circumference);
dbms_output.put_line('Area: ' || area);
END;
/
When the above code is executed at the SQL prompt, it produces the following
result −
Radius: 9.5
Diameter: 19
Circumference: 59.69
Area: 283.53
Pl/SQL procedure successfully completed.
The PL/SQL Literals
A literal is an explicit numeric, character, string, or Boolean value not represented
by an identifier. For example, TRUE, 786, NULL, 'tutorialspoint' are all literals of
type Boolean, number, or string. PL/SQL, literals are case-sensitive. PL/SQL
supports the following kinds of literals −
Numeric Literals
In this chapter, we will discuss constants and literals in PL/SQL. A constant holds
a value that once declared, does not change in the program. A constant declaration
specifies its name, data type, and value, and allocates storage for it. The
declaration can also impose the NOT NULL constraint.
Declaring a Constant
A constant is declared using the CONSTANT keyword. It requires an initial value
and does not allow that value to be changed. For example −
PI CONSTANT NUMBER := 3.141592654;
DECLARE
-- constant declaration
pi constant number := 3.141592654;
-- other declarations
radius number(5,2);
dia number(5,2);
circumference number(7, 2);
area number (10, 2);
BEGIN
-- processing
radius := 9.5;
dia := radius * 2;
circumference := 2.0 * pi * radius;
area := pi * radius * radius;
-- output
dbms_output.put_line('Radius: ' || radius);
dbms_output.put_line('Diameter: ' || dia);
dbms_output.put_line('Circumference: ' || circumference);
dbms_output.put_line('Area: ' || area);
END;
/
When the above code is executed at the SQL prompt, it produces the following
result −
Radius: 9.5
Diameter: 19
Circumference: 59.69
Area: 283.53
Pl/SQL procedure successfully completed.
The PL/SQL Literals
A literal is an explicit numeric, character, string, or Boolean value not represented
by an identifier. For example, TRUE, 786, NULL, 'tutorialspoint' are all literals of
type Boolean, number, or string. PL/SQL, literals are case-sensitive. PL/SQL
supports the following kinds of literals −
Numeric Literals
