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

Varray


Oracle Database 8i introduced varrays as a modified format of a nested table. The varray or variable size array is quite similar to nested tables but bounded in nature. The varray declaration includes the count of elements that a varray can accommodate. The minimum varray index is 1, the current size is the total number of elements, and the maximum limit is the varray size. At any moment, the current size cannot exceed the maximum limit. Varrays are appropriately used when you know the maximum number of elements in a collection structure.

Like nested tables, varrays can be created in the database as schema objects as well as in a PL/SQL block. When created in the database as a schema object, varrays can be referenced in PL/SQL program units as variables, parameters and function return types. A table can have a column of a varray type. An object type can have an attribute of a varray type. The syntax for varrays, when defined as a database collection type, is as follows:

CREATE [OR REPLACE...