Create a procedure to calculate a percentage and an average for a given sales transaction.
A procedure is created by using the CREATE PROCEDURE command and blocks of PL/SQL statements. Use the SlideShow below to see how a procedure is built.
The Slide Show walks you through creating a procedure that accepts a primary key field as an incoming parameter and sends two calculated values back to two outgoing parameters.
: How do you write your own built-in SQL functions?
: A function is a PL/SQL named block that returns a value. It is commonly used to convert or assign values.
Note the following: 1) A procedure is executed, 2) a function is called, as in the example below:
n_area := calc_area(11,22);
In the code fragment above, the area is calculated using a procedure named
and a function named
The procedure was passed three values and it copied the calculated area into the
variable when the procedure exited.
The next line uses a function that is
- passed two values,
- calculates the area, and
- returns that value,
which is assigned to the
Notice that the function is used directly in the assignment operation. A function is defined in the format below.