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

PL/SQL Function Result Cache


You must create a PL/SQL function with a RESULT_CACHE clause to add its result to the PL/SQL function result cache. When a cache-enabled PL/SQL function is invoked for the first time, the database looks into the PL/SQL result cache for its result with the matching arguments. If the result is found, it is returned to the calling environment without executing the function body. If the result is not found, the function body is executed and the result is stored in the PL/SQL function cache. Upon subsequent function calls for the same input parameters, the result is fetched directly from the cache.

Note that a result cache function doesn't need the dependent database tables to be result-cached.

Note

Oracle Database 11g Release 1 used the RELIES_ON clause to specify the dependent data sources whose state would affect the status of the cached result. The clause was deprecated in Oracle Database 11g Release 2.

Does it sound similar to deterministic functions?

Developers who...