Oracle PL/SQL Programming, 5th Edition

So This Is PL/SQL

If you are completely new to programming or to working with PL/SQL (or even SQL, for that matter), learning PL/SQL may seem an intimidating prospect. If this is the case, don’t fret! I am confident that you will find it easier than you think. There are two reasons for my optimism:

• Computer languages in general are not that hard to learn, at least compared to a second or third “human language.” The reason? It’s simply that computers are not particularly smart (they “think”—perform operations—rapidly, but not at all creatively). We must rely on a very rigid syntax in order to tell a computer what we want it to do. So the resulting language is also rigid (no exceptions!) and therefore easier for us to pick up.

• PL/SQL truly is an easy language, compared to other programming languages. It relies on a highly structured “block” design with different sections, all identified with explicit, self-documenting keywords.

Let’s look at a few examples that demonstrate some key elements of both PL/SQL structure and functionality.

Integration with SQL

One of the most important aspects of PL/SQL is its tight integration with SQL. You don’t need to rely on any intermediate software “glue” such as ODBC (Open Database Connectivity) or JDBC (Java Database Connectivity) to run SQL statements in your PL/SQL programs. Instead, you just insert the UPDATE or SELECT into your code, as shown here:

 1 DECLARE 2 l_book_count INTEGER; 3 4 BEGIN 5 SELECT COUNT(*) 6 INTO l_book_count 7 FROM books 8 WHERE ...