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

Introduction to collections


A collection is an array like homogeneous single-dimensional structure, which holds a set of elements of similar data type. Each cell in a collection, and hence, each element, is uniquely identified by its position index or the subscript. The element or the value contained in a cell can be of a valid SQL data type or a user-defined type. There are three types of collections: associative array; nested table; and varray.

A collection can be bounded or unbounded on the basis of it's collection size. Bounded collections have a fixed number of elements, as in arrays. Unbounded collections can have any number of elements. Varrays are bounded collections while the associative arrays and nested tables are unbounded.

On the basis of persistence in the database, a collection can be either a persistent or non-persistent collection. A persistent or SQL collection can either be created in the Oracle Database schema or declared within the PL/SQL block. A PL/SQL or non-persistent...