Introduction

A business traveler's cell phone beeps; he's received a text message informing him that his flight's departure gate has been changed. A system administrator receives a message on her pager alerting her that a critical server has gone down. An inventory manager at a grocery store gets an email telling him that the stock level for a popular product has dropped below the threshold for reordering.

These are examples of personalized notifications reaching people when the information is most relevant, on whatever device they have available. In today's information-driven world, notifications such as these have real business value. Timely information can attract customers, make employees more productive, and enable agile decision making. The software systems that generate and deliver these notifications extend the reach of information beyond the corporate desktop.

Building notification software presents several challenges. Every day, people are bombarded with an overload of irrelevant information. For a notification system to add value, it must deliver only targeted, focused information based on the needs and preferences of each user. Doing this correctly requires sophisticated matching and filtering capabilities.

Also, notification systems must be reliable because they're often used to deliver mission-critical alerts. They must be scalable so that they can support millions of users and high volumes of data, without requiring excessive hardware. They must be manageable and fit seamlessly into an existing IT infrastructurethey must not burden the operators who maintain them. Most importantly, notification systems must be secure.

Microsoft SQL Server 2005 Notification Services is a platform for building notification applications that meet all these requirements. It provides a reliable, manageable, secure base for your applications, with a rich, scalable matching engine that can filter an information stream based on the subscriptions of millions of users.

Notification Services offers a simple, declarative programming model that lets you build your application with much less development effort than would be required if you were building it from scratch. Using this programming model, you can get a working prototype of a typical application running in just a single day. Furthermore, the platform offers a number of sophisticated features, such as support for multiple languages and device types, scheduled subscriptions, user-defined matching logic, and multicast delivery, that you can incorporate into your applications by setting a few options. These kinds of beyond-the-obvious features set the most advanced notification applications apart from the rest.

This book is about building notification applications with Microsoft SQL Server 2005 Notification Services. It covers general Notification Services concepts, describes specific coding techniques used to build applications, and walks you through the process of developing a sample application, from the initial design and prototype to final deployment and administration. In addition to the basics, it covers more advanced concepts for developers who want to get the most out of the Notification Services functionality.