Microsoft SQL Server 2012 Bible

Configuring a Message Queue

Service Broker uses a messaging or dialog metaphor, but there's much more to Service Broker than just the messages. The Service Broker uses the following objects, which must be defined in the following order:

1. Message types define the format and structure of a message.

2. Contracts define the agreement between the initiating service and the target, including the message type(s). Queues hold the messages for one or more services.

3. Services store messages in a queue and either send or receive messages as the initiating service or the target service, respectively.

Other than defining the message type as XML and naming the objects, there isn't much complexity to setting up a Service Broker database. Although the messages don't have to be XML, they almost always will be. That's because the data definition language, or DDL, does all the work; and Service Broker is a message-agnostic work queue that serves as an infrastructure for the messages. There's more work in placing messages on and taking messages off the queue.

The first step to is to enable Service Broker on the database. Then create a Service Broker queue by defining a message type and a contract that uses that message type:

ALTER DATABASE AdventureWorks2012 SET ENABLE_BROKER;
GO
CREATE MESSAGE TYPE HelloWorldMessage
 VALIDATION = WELL_FORMED_XML ;
GO
CREATE CONTRACT HelloWorldContract
 ( HelloWorldMessage SENT BY INITIATOR);
GO

The initiator and target queues are created using the CREATE ...