The %TYPE Attribute in PL/pgSQL

The %TYPE attribute

• Is used to declare a variable according to : 
• A database column definition
• Another declared variable
• Is prefixed with :
• The database table and column
• The name of the declared variable

Declaring Variables with the %TYPE Attribute


Syntax :
identifier table.column_name%TYPE;


Examples :
emp_name emp.ename%TYPE;
balance NUMERIC;
min_balance balance%TYPE := 1000;

Use of Variables in PL/pgSQL

Variables can be used for :

• Temporary storage of data
• Manipulation of stored values
• Reusability

Handling Variables in PL/pgSQL

Variables are :

• Declared and initialized in the declarative section
• Used and assigned new values in the executable section
• Passed as parameters to PL/pgSQL subprograms
• Used to hold the output of a PL/pgSQL subprogram

         DECLARE
         emp_hiredate DATE;
         emp_deptno NUMERIC := 10;
         location VARCHAR(13) := 'Atlanta';

Guidelines for Declaring PL/pgSQL Variables

• Avoid using column names as identifiers.
• Use the NOT NULL constraint when the variable must hold a value.