Introduction

In this tutorial, we will cover the basics of declaring variables in PL/SQL.

Variable Declaration

In PL/SQL, a variable is a storage location that holds a value. To declare a variable, you need to specify its data type and name. The basic syntax for declaring a variable is:

variable_name datatype [NOT NULL := value];

Here is an example of declaring a variable named x of the data type INTEGER and assigning it a value of 10:

DECLARE
  x INTEGER := 10;
BEGIN
  -- statements
END;

You can also declare multiple variables of the same data type in a single statement:

DECLARE
  x INTEGER := 10;
  y INTEGER := 20;
  z INTEGER := 30;
BEGIN
  -- statements
END;

Data Types

PL/SQL supports various data types such as:

1. INTEGER: It stores whole numbers.

DECLARE
  x INTEGER := 10;
BEGIN
  -- statements
END;

2. VARCHAR2: It stores variable-length character strings. The maximum size can be specified in bytes or characters.

DECLARE
  x VARCHAR2(10) := 'Hello';
BEGIN
  -- statements
END;

3. DATE: It stores date and time values.

DECLARE
  x DATE := SYSDATE;
BEGIN
  -- statements
END;

4. BOOLEAN: It stores TRUE, FALSE or NULL values.

DECLARE
  x BOOLEAN := TRUE;
BEGIN
  -- statements
END;

Conclusion

In this tutorial, we have covered the basics of declaring variables in PL/SQL. We have discussed the syntax and examples of declaring variables of different data types such as INTEGER, VARCHAR2, DATE and BOOLEAN. Remember to always specify the data type and assign a value or specify the default value when declaring a variable.