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The question is, “Where do I start?” In the beginning, Codd created the paper “A Relational Model of Data for Large Shared Data Banks.” Now the relational database was formless and empty, darkness was over the surface of the media, and the spirit of Codd was hovering over the requirements. Codd said, “Let there be Alpha,” but as usual, the development team said, “Let there be something else,” so SEQUEL (SQL) was created. Codd saw that SQL wasn’t what he had in mind, but it was too late, for the Ellison separated the darkness from the SQL and called it Oracle. OK, that’s enough of that silliness. But that’s the short of it.

Don’t know any 60’s speak? Back in the 1960s, calling an authority figure square was meant to be an insult. It meant “the man” was always playing by and enforcing the rules. That could be a real drag, a downer, something that could blow your scene. However, when it comes to a programming language, it’s good to be square.

OK, now you’re going to hear me start repeating myself. Now you’re going to hear me start repeating myself. It’s not necessarily because I’m old, although that may have something to do with it, but rather because I introduced some of the topics covered in this chapter in Chapters 1 and 2.

Now we begin our journey of using SQL in PL/SQL. We’ll start out slowly, inserting one row at a time, then updating one row at a time, then deleting one row at a time, and finally selecting one row at a time. I take this approach because you first have to insert data into a database before you can update, delete or select it. I call these kinds of SQL statements , because they return one set of results. So let’s get started by putting some data into the database.

In our last episode, we left off with our “would-be” PL/SQL programmer trying to retrieve the first names of the Doe family members from table WORKER_T using a singleton SELECT. Little did our programmer know that Oracle has already solved this problem, and the magic required to pull off such a feat was already in his hands.

It was the philosopher George Santayana who stated, “Those who cannot remember the past are condemned to repeat it.” Philosophy is an interesting pursuit from my point of view, because it looks at very high-level abstract patterns of behavior. Patterns are repeated data or behavior of a simple or complex nature.

I believe programmers are no better than their knowledge of the debugging tools available for the programming language they’re using. Why? Well first, all programmers make coding mistakes. I often remark that the day I code something that compiles and runs correctly the first time, I’m going to retire, because that would be the peak of my programming career. Second, programmers make logic mistakes. When is the last time you had to write some parsing code? That’s one of the toughest types of programming to get right the first, second, third, or nth time around.

And then test again! By now, you know I like to try to be funny, and most of the time I fail. We all have to fail at something, right? Regardless, the title of this chapter is not a joke on my part. After 20 plus years of enterprise application development, I’ve found that the actual application development process for programmers consists of three high-level tasks:

Once, when I was a young executive, I reported to the chief financial officer (CFO). Upon arriving at the new organization, I formulated a strategy to bring the company’s computer technology up-to-date. Part of that plan was to provide each computer user in the organization with a computer that best suited that user’s needs. This meant that executive administrators got high-powered desktop computers, while executives and consultants were armed with top-of-the-line notebooks. Not only did we make sure everyone was using the latest office automation software and groupware, we also built a state-of-the-art Executive Information System (EIS) that was tightly integrated with the accounting system.

Polymorphism is the subject of this chapter. No, it’s not some kind of New Age religion; it’s about using the same message (or command) in order to get the same result, but for different kinds of objects. Let’s look at a simple example. Figure 10-1 shows the use of the command draw() for three different geometric shapes: a square, a triangle, and a circle.