MS BizTalkServer

Messaging

How BizTalk Server Works

At the core of BizTalk Server 2009 are the Messaging Engine and the Orchestration Engine, which provide the underlying architecture for integrating and exchanging messages between various services, both within and outside your organization. The BizTalk Messaging Engine:

• Receives inbound messages.
• Parses inbound messages to identify their specific formats.
• Evaluates message content to identify how the message is to be routed and processed.
• Delivers messages to their respective destinations.
• Tracks the status and state of documents.

The BizTalk Orchestration Engine, in contrast, coordinates and schedules message processing and performs complex logic on the message as it is passed through a defined workflow.

Building Schemas

The schemas processed by BizTalk Server can come from a variety of different sources. A schema definition might be predefined by some external application or it might be sent by a trading partner. To integrate with an existing EDI application, BizTalk Server provides over 8,000 different schemas to support existing EDIFACT and X12 message standards. However, in many cases you will have to create the schemas yourself for XML or flat-file document structures by using BizTalk Editor.

BizTalk Server 2009 natively supports the following schema types:

• XML:
  The BizTalk messaging and orchestration engines require that all messages be in XML format. An XML schema defines the hierarchical structure of an XML message. BizTalk Server identifies and validates all messages against an associated schema.
• Flat-file:
  A flat-file schema defines the structure of messages that are received in a flat-file format. A flat file can be either delimited or positional. The XML Schema Definition language (XSD) does not natively support the flat-file structure; therefore, BizTalk Server uses the annotation capabilities of XSD to store this extra information within the XSD schema itself. BizTalk Server defines a rich set of specific annotation tags that can be used to store all of the required additional information.
• EDI:
  BizTalk Server enables the creation and use of schemas to represent standard EDI document formats such in EDIFACT and X12. An EDI message is a variation of a text message and does not use typical delimiters such as carriage returns and linefeeds. As with flat-file schemas, BizTalk Server uses the annotation capabilities of XSD to store the extra information related to the format of the EDI messages.

Orchestration

A business process is a set of actions that, taken together, meet a specific business need. Business process automation enables the coordination of common business processes, for example approving a purchase order, with people and business applications—such as Enterprise Resource Planning (ERP), Customer Relationship Management (CRM), or other LOB applications. These processes frequently start as manual tasks that require integration and input from various systems and individuals. The process may take hours, days, weeks, or months to complete. BizTalk orchestration is a flexible and powerful capability that provides various services and tools to enable you to design, automate, and manage business processes. Similar to traditional procedural programming languages, an orchestration represents the underlying logic for processing messages. BizTalk orchestration provides a transactional programming model that includes support for exception handling and recovery from failed transactions. You can define two types of transactions when creating an orchestration:

• Atomic transaction:
  Enables a transaction to automatically role back to a previous state in case the transaction does not successfully complete.
• Long running transaction:
  Can span days, weeks, and longer time durations, contain nested transactions, and use custom exception handling to recover from error scenarios.

As a result, orchestrations provide you the flexibility to define the course of action in the event of a business process failure.

Orchestration Designer

Orchestration Designer provides a design surface that enables you to create visual representations of your business processes. The design surface is a working canvas where you drag different shapes from the Toolbox as shown in Figure 8. The shapes correspond to the different actions that you need to perform when processing a message. In most cases, you must configure options for each shape that you use when you build the orchestration. The design surface is divided into three areas: one Process Area and two Port Surfaces. The Process Area contains shapes that describe the actual process flow of the orchestration. For example, scope shapes helps you define transactions in a business process. A scope contains one or more blocks. It has a body and can optionally have any number of exception-handling blocks as well as a compensation block appended to it. The Process Area of the design surface is flanked on both sides by Port Surfaces, which contain only Port and Role Link shapes that interact with the send and receive shapes in the Process Area. You can use either side (right or left) of a Port Surface to create a send or receive port. This enables you to create well-documented orchestrations that have fewer crisscrossing connectors, making your orchestrations easier to read.

The Business Rules Framework

BizTalk Server 2009 includes the Business Rules Framework as a stand-alone .NET-compliant class library that includes a number of modules, support components, and tools. The primary modules include the Business Rule Composer for constructing policies, the Rule Engine Deployment Wizard for deploying policies created in the Business Rule Composer, and the Run-Time Business Rule Engine that executes policies on behalf of a host application. You can integrate business rules into your orchestrations to support a variety of scenarios:

• Use rules instead of coding and recoding constantly changing business policies and logic within your complex business processes. Incorporate a call and allow information workers to update business rules.
• Use rules to evaluate business logic and to determine when a business process requires a variable delay. For example, you might set up a loop to check on the status of an item to determine whether the item is in stock. After initially checking the stock of an item that is not available, the rule delay would be one minute. The next time, the rule would wait five minutes before executing; the time after that, the rule would wait 30 minutes before executing; and so on.
• Use rules to determine the execution path for a business process, basing the determination on the results of the rule execution. For example, if a customer does not exist for a particular purchase order, you could route the document to another business process to add the customer to the database before continuing to process the purchase order.

The BizTalk Orchestration Engine, in contrast, coordinates and schedules message processing and performs complex logic on the message as it is passed through a defined workflow.

Business to Business Integration

BizTalk Server 2009 enables you to integrate trading partners into your existing business processes. A trading partner can be an external company or even a department within your own organization. BizTalk Server includes a number of capabilities to simplify the integration of your business processes with your trading partners and the management of trading partner relationships:

• Native support for EDI and AS2 protocols:
  BizTalk Server provides data exchange options including a native engine that provides integrated support for Electronic Data Interchange (EDI) data (including both X12 and EDIFACT, and HIPAA support) and Applicability Statement 2 (AS2) data for EDI over the Internet.
• Trading Partner Management:
  BizTalk Server provides a common storage database to store and manage all trading partner information. This information is maintained using the BizTalk Server Administration console.
• BizTalk Server accelerators:
  Accelerators are used to integrate BizTalk Server with a broad spectrum of business scenarios and industries. Accelerators include specific BizTalk Server components, samples, and guides that help to reduce the time, effort, and costs associated with developing an industry-specific solution.