Book Image

Getting Started with Oracle Event Processing 11g

Book Image

Getting Started with Oracle Event Processing 11g

Overview of this book

Events are everywhere, events which can have positive or negative impacts on our lives and important business decisions. These events can impact a company's success, failure, and profitability. Technology now allows people from all walks of life to create Event Driven applications that will immediately and completely respond to the events that affect you and your business. So you are much more responsive to your customers, and competitive threats, and can take advantage of transient time sensitive situations. "Getting Started with Oracle Event Processing" will let you benefit from the skills and years of experience from the original pioneers who were the driving force behind this immensely flexible, complete, and award winning Event Stream Processing technology. It provides all of the information needed to rapidly deliver and understand Event Driven Architecture (EDA) Applications. These can then be executed on the comprehensive and powerful integral Java Event Server platform which utilizes the hardware and operating system.After an introduction into the benefits and uses of Event Stream Processing, this book uses tutorials and practical examples to teach you how to create valuable and rewarding Event Driven foundational applications. First you will learn how to solve Event Stream Processing problems, followed by the fundamentals of building an Oracle Event processing application in a step by step fashion. Exciting and unique topics are then covered: application construction, the powerful capabilities of the Oracle Event Processing language, CQL, monitoring and managing these applications, and the fascinating domain of real-time Geospatial Movement Analysis. Getting Started with Oracle Event Processing will provide a unique perspective on product creation, evolution and a solid understanding on how to effectively use the product.
Table of Contents (19 chapters)
Getting Started with Oracle Event Processing 11g
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

SQL as a foundation


You have learned how to transform a stream into a relation by using WINDOW operators, and then how to convert a relation back to a stream by using the ISTREAM/DSTREAM/RSTREAM family of operators. But why do we convert to relations to begin with? By converting streams to relations, you can leverage the full power of SQL, as we are used to it in a database. After all, SQL works directly on top of relations.

CQL supports most of the SQL99 commands, which we explore in this section.

Joins

In CQL, you can join multiple sources, but all sources must be relations or streams that have been converted to relations using a window operator.

Joins are very useful as a mechanism for enriching events with contextual data that don't change often. For example, consider the following query that enriches a stock market feed event with the full address of the said stock:

SELECT 
  S1.symbol as symbol
  fullName
FROM
  reutersMarketFeed[RANGE 60 SECONDS] AS S1, 
  tickerListing AS R1
WHERE
  S1...