Microsoft® SQL Server® 2012 Bible

647

CHAPTER

25

Asynchronous Messaging with

Service Broker

IN THIS CHAPTER

Using Message Multicast

Defi ning a Work Queue

Queuing Messages

Managing Dialogs

S

ervice Broker is one of the most powerful features of SQL Server. This feature is essential in

any Service-Oriented Architecture (SOA) data store architecture because it enables you to

send asynchronous messaging and add work queues to a database to provide high fl exibility,

extensibility, and scalability.

If you’ve ever built a table to hold pending work, such as orders to be processed by a Material

Resource Planning (MRP) system, then you’ve built a work queue. In one application, Service Broker

is just that — a high-performance, wide-payload work queue manager integrated into SQL Server

with DDL and monitoring capabilities, all rolled into one application.

For example, suppose that you want to pass sales order data to another database application that

notifi es customers that their order has been shipped. You can use Service Broker to send this mes-

sage to another database where an e-mail message is queued to be sent out. The outgoing e-mails

may have some sort of delay due to restrictions imposed by the e-mail provider. An independent

process can manage e-mail transmissions without affecting the main sales database. You might also

have a loosely coupled application in which communications cannot be guaranteed at all times. If

data goes to a queue, it can be sent whenever the communications pipeline is open. Figure 25-1

illustrates an asynchronous shipping notifi cation example using Service Broker.

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