Service Broker (SQL Server)

SQL Server 2005 and higher provides the service broker, which manages a queue of services. Applications that use Service Broker communicate by sending messages to one another as part of a conversation. The participants in a conversation must agree on the name and content of each message.

• Message Types (SQL Server)
  Message types define the type of data that a message can contain. You create identical message types in each database that participates in a conversation.
• Contracts (SQL Server)
  Contracts define the message types used in a Service Broker conversation and also determine which side of the conversation can send messages of that type. Each conversation follows a contract. The initiating service specifies the contract for the conversation when the conversation begins. The target service specifies the contracts that the target service accepts conversations for. PowerDesigner models contracts as extended objects with a stereotype of <<Contract>>.
• Message Contracts (SQL Server)
  Message contracts are intermediary objects that are used to include a single message in multiple contracts. Message contracts are modeled as extended objects with a stereotype of <<MessageContract>>.
• Queues (SQL Server)
  When a message arrives for a service, Service Broker places the message on the queue associated with the service. PowerDesigner models queues as extended objects with a stereotype of <<Queue>>.
• Event Notifications (SQL Server)
  An event notification sends information about a database or server event to a service broker service. Event notifications are created only by using Transact-SQL statements. PowerDesigner models event notifications as extended objects with a stereotype of <<EventNotification>>.
• Services (SQL Server)
  Services are specific tasks or set of tasks. Service Broker uses the name of the service to route messages, deliver messages to the correct queue within a database, and enforce the contract for a conversation. PowerDesigner models services as extended objects with a stereotype of <<Service>>.
• Routes (SQL Server)
  Routes appear in the routing table for the database. For outgoing messages, Service Broker determines routing by checking the routing table in the local database. For messages on conversations that originate in another instance, including messages to be forwarded, Service Broker checks the routes in msdb. PowerDesigner models routes as extended objects with a stereotype of <<Route>>.
• Remote Service Bindings (SQL Server)
  Remote service bindings create a binding that defines the security credentials to use to initiate a conversation with a remote service. PowerDesigner models remote service bindings as extended objects with a stereotype of <<RemoteServiceBinding>>.