The declaration section of the PLSQL bloke is where you can set up variables that will be used throughout the code – a variable is used to store temp data for use in that specific code execution.
[ CONSTANT ] [ := ];
When setting a variable within PLSQL you can set it to be a CONSTANT i.e. the specified initial value set cannot be changed. You can also set a default value for a standard variable.
v_employee_surname VARCHAR2(50) := ‘Smith’;
You can also set the datatype as a table type – to mimic what the table datatype is.
t_employee_name EMPLOYEE.surname%TYPE := ‘Smith’;