Resilient Oracle PL/SQL

Chapter 7. A Process-Centric, Feature-Based Mini Project

In this chapter, you’ll see an overview of all the resilient PL/SQL requirements brought together as part of a solution. The elements include the following:

1. Define the requirements

2. Build a basic invoice outline

3. Create the schema

4. Test the schema

5. Feature description

6. The PL/SQL toolbox elements needed to build a solution

7. Tests

8. Building a resilient PL/SQL solution

9. Verifying the solution by invoking it from a high-level language

Each of these elements is described in the following sections.

A Brief Note on Invoices

Just in case you’re not familiar with invoices, note that they are used in businesses to record an amount of money owed to the business, usually for some item or items of work. An invoice is issued to a customer to record the work done and the amount of money owed for that work. Various other items of information are generally included in an invoice, as you’ll see later on.

Invoices can be considered a critical business component: they feed into accounting systems and contribute to tax calculations. Another aspect of invoices is that a copy of a given invoice is often sent to a customer. Thus, it’s very important that the content of an invoice is both clear and accurate. The vagueness of the second requirement is not a reflection of the low importance of the end result; rather, the author of the requirement is probably assuming the developers have business knowledge that they may or may not have. ...