Book Image

Advanced Oracle PL/SQL Developer's Guide (Second Edition) - Second Edition

By : Saurabh K. Gupta
Book Image

Advanced Oracle PL/SQL Developer's Guide (Second Edition) - Second Edition

By: Saurabh K. Gupta

Overview of this book

Oracle Database is one of the most popular databases and allows users to make efficient use of their resources and to enhance service levels while reducing the IT costs incurred. Oracle Database is sometimes compared with Microsoft SQL Server, however, Oracle Database clearly supersedes SQL server in terms of high availability and addressing planned and unplanned downtime. Oracle PL/SQL provides a rich platform for application developers to code and build scalable database applications and introduces multiple new features and enhancements to improve development experience. Advanced Oracle PL/SQL Developer's Guide, Second Edition is a handy technical reference for seasoned professionals in the database development space. This book starts with a refresher of fundamental concepts of PL/SQL, such as anonymous block, subprograms, and exceptions, and prepares you for the upcoming advanced concepts. The next chapter introduces you to the new features of Oracle Database 12c, not limited to PL/SQL. In this chapter, you will understand some of the most talked about features such as Multitenant and Database In-Memory. Moving forward, each chapter introduces advanced concepts with the help of demonstrations, and provides you with the latest update from Oracle Database 12c context. This helps you to visualize the pre- and post-applications of a feature over the database releases. By the end of this book, you will have become an expert in PL/SQL programming and will be able to implement advanced concepts of PL/SQL for efficient management of Oracle Database.
Table of Contents (19 chapters)
Advanced Oracle PL/SQL Developer's Guide Second Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Chapter 4. Using Collections

A collection is a single-dimensional structure of homogeneous elements. Behaviorally speaking, it is quite similar to an array and a list structure available in other third generation languages. First introduced in Oracle 7 as PL/SQL tables, Oracle 8i rebranded collections as Index-by tables. Oracle 8i also introduced persistent collection types, namely nested tables and varrays. Oracle Database 9i renamed Index-by-tables to associative arrays.

Oracle Database offers a wide scope of usability of collections in PL/SQL programming. The language semantics not only allow you to create and maintain collections, but also provides multiple methods for array operations. This chapter helps you to understand the collection types in Oracle and, most importantly, which types suit a given problem. The chapter outline looks like this:

  • An introduction to collections

    • Categorization

    • Selection of an appropriate collection type

  • Associative arrays

  • Nested tables

  • Varrays

  • PL/SQL collection...