PL/SQL Constants and Literals in Oracle PL/SQL

In this article, we will discuss PL/SQL constants and literals in Oracle PL/SQL tutorial.

If you missed the previous article of Variables in PL/SQL, then please click here.

let’s start now …

A PL/SQL constants hold a value that does not change during the whole execution of the program. The declaration of a constant specifies its name, data type, and value, and allocates storage for it.

vconstant_name CONSTANT datatype := VALUE; 

• constant_name is that we are declaring.
• The CONSTANT word is restrained, and it ensures that the value does not change throughout the program.
• VALUE – The value which must be assigned to a constant when it is declared. You can’t give it later.

PL/SQL constants examples:

DECLARE
    co_payment_term   CONSTANT NUMBER   := 45; -- days 
    co_payment_status CONSTANT BOOLEAN  := FALSE; 
BEGIN
    NULL;
END;

If you try to change the co_payment_term in the execution section, PL/SQL will give an error, for example:

DECLARE
    co_payment_term   CONSTANT NUMBER   := 40; -- days 
    co_payment_status CONSTANT BOOLEAN  := FALSE; 
BEGIN
    co_payment_term := 30; -- error
END;

Here is the error message:

PLS-00363: expression 'CO_PAY_TERM' cannot be used as an assignment target

Oracle PL/SQL, a literal is an equivalent as a constant. PL/SQL, literals are case-sensitive. A PL/SQL literal is a value that is not represented by an identifier; it is simply a value.

1. Numeric Literals
2. Character Literals
3. String Literals
4. BOOLEAN Literals
5. Date and Time Literals

In this article, we are discussed about the Constant in PL/SQL and also different types of Literals in PL/SQL. It is the basics concept of Oracle PL/SQL Tutorials. In the next article, we will discuss the different operators of PL/SQL.

Thank You 🙂