How many of us would believe that PL/SQL was introduced as a scripting language for executing a bunch of SQL scripts? Well, that's true. With the growing need to build computational logic and condition-based constructs, and to manage exception rules within databases, Oracle Corporation first released PL/SQL along with Oracle Database Version 6.0 with a limited set of capabilities. Within its capacity, PL/SQL was capable of creating program units that could not be stored inside the database. Eventually, Oracle's release in the application line, SQL *Forms version V3.0, included the PL/SQL engine and allowed developers to implement the application logic through procedures. Back then, PL/SQL used to be part of the transaction processing option in Oracle 6 and the procedural option in Oracle 7. Since the time of its ingenuous beginning, PL/SQL has matured immensely as a standard feature of Oracle Database. It has been enthusiastically received by the developer community, and the credit goes to its support for advanced elements such as modular programming, encapsulation, support for objects and collections, program overloading, native and dynamic SQL, and exception handling.

PL/SQL is loosely derived from Ada (named after Ada Lovelace, an English mathematician who is regarded as the first computer programmer), a high-level programming language, which complies with the advanced programming elements. Building a database backend for an application demands the ability to design the database architecture, skills to code complex business logics, and expertise in administering and protecting the database environment. One of the principal reasons why PL/SQL is a key enabler in the development phase is its tight integration with Oracle's SQL language. In addition to this, it provides a rich platform for implementing the business logic in the Oracle Database layer and store them as procedures or functions for subsequent use. As a procedural language, PL/SQL provides a diverse range of datatypes, iterative and control constructs, conditional statements, and exception handlers.

In a standard software development space, an Oracle database developer is expected to get involved in schema design; code business logics on the server side by using functions, procedures, or packages; implement action rules by using triggers; and support client-side programs in setting up the application interface. While building the server-side code, developers should understand that their code contributes to the application's performance and scalability. Language basics are expected to be resilient, but while building robust and secure applications using PL/SQL, developers must take advantage of best practices and try to use advanced language features. This book focuses on the advanced features of PL/SQL validated up to the latest Oracle Database 12c.

Learning by example has always been a well-attested approach for diving deep into a concept. This book will enable you to master the latest enhancements and new features of Oracle Database 12c. For efficient reading, you just have to be familiar with the PL/SQL fundamentals so that you can relate to the evolution of an advanced feature from its ever-expanding roots.

This book closely follows the outline of the Oracle University certification; that is, the Oracle Certified Advanced PL/SQL Developer Professional (1Z0-146) exam. One of the most sought after certifications in the developer community, the 1Z0-146 certification's objectives are quite comprehensive, and touch upon the various progressive areas of PL/SQL. To name a few, PL/SQL code performance, maintenance, bulk processing techniques, PL/SQL collections, security implementation, and the handling of large objects. For certification aspirants, this book will serve as a one-stop exam guide. At many stages, this book goes beyond the certification objectives and attempts to build a deep understanding of the concepts. Therefore, mid-level database developers will find this book a handy language reference and would be keen to have it on their bookshelves.

My last work on the same subject will remain close to my heart, but this one is straight from my experience. I hope that this book will help you improve your PL/SQL development skills and gain confidence in using advanced features, along with meticulous familiarization of Oracle Database 12c.