When to Use AICs
So, when would you need to create an AIC? Well, you might need to write one or use a prebuilt AIC when you need to integrate with an external application system, such as SAP, or when you need to update data in an SQL database, such as SQL Server or Oracle. You may also need to write one when you integrate with a Web service. Each of these is depicted in Figure 17.1.
Figure 17.1. Using AIC to connect to various applications.
Figure 17.1 shows how an AIC on a BizTalk Messaging Port can be used to integrate to an ERP system (SAP R/3), databases, other COM components, or a Web service.
In BizTalk, messages can originate in one of two ways: BizTalk Messaging and BizTalk Orchestration. AICs are only required when integrating an application through a BizTalk Messaging transport. BizTalk Orchestration schedules do not require COM components attached to schedule actions to implement the special AIC interface. If you have implemented your business process using both messaging and orchestration services, you have the option of integrating external applications using either an AIC or standard COM component.
Note
Remember, you only need to implement the AIC when you are integrating with applications via BizTalk Messaging Port. In BizTalk Orchestration, when you use COM+ implementation shapes you do not need to implement any special COM interface in your COM components, such as the IBTSAppIntegration interface.
Typically, you write AICs in Enterprise Application Integration Scenarios, such as when you want to integrate Commerce One (BuySite) to your ERP system (SAP R/3). For example, the market site generates a purchase order (PO) and requires updating the ERP system and verifying that sufficient inventory and customer credit exists for the PO to be honored.
Figure 17.2 shows how AICs are used from a BizTalk Orchestration. In this example, a new user account is created in the Active Directory and then an Exchange Mailbox is created. The sequencing in Orchestration ensures that the new user is created first before creating the mailbox.
Figure 17.2. BizTalk Orchestration schedule using AICs to integrate applications.
