PL/SQL Functions and Procedures.
To declare functions and / or procedures in PL/SQL is very straight forward once you know the keywords and syntax.
To declare a function the syntax is a follows:
FUNCTION calculate_term(maturity_start_date IN DATE,
maturity_end_date IN DATE) RETURN NUMBER;
The IN keyword specifies that the parameter is an input only parameter. The
RETURN keyword determines what data type will be returned to the caller.
PROCEDURE Load(di_fin_year_code IN CHAR,
di_fin_month_code IN CHAR, a_perform_s INTEGER DEFAULT 1);
The DEFAULT keyword specifies that the parameter has a default value. That means that if the
variable value is 1 the variable may be omitted by the caller.