BAPI/ALE Integration (SAP Library - BAPI Programming Guide CA-BFA))

BAPI/ALE Integration

BAPIs are integrated into the ALE communication model. ALE communication is asynchronous and message-based. ALE communication is the preferred way to integrate distributed R/3 Systems, for example, for distributing master data.

Since Release 4.0 BAPIs are the standardized interfaces for ALE-supported communication. ALE services, such as asynchronous BAPI calls, distribution model, monitoring and error handling can be used for BAPIs. The IDoc types required for the ALE services can be generated from BAPIs.

See also: Using ALE Services.

When you use BAPIs for asynchronous messaging, the application in the sending system calls the generated ALE IDoc interface instead of the BAPI. The ALE IDoc interface performs the following tasks:

Creates an IDoc from the BAPI data
Sends the IDoc to the target system
Receives the IDoc in the target system, creates the BAPI data from the IDoc and calls the BAPI

You can use Transaction BDBG to create the other objects required for the asynchronous communication (message type, IDoc type, inbound and outbound function module).

A BAPI should only be implemented as an asynchronous interface, if at least of the following conditions is satisfied:

Database changes are consistent in all systems
Data must be updated consistently on a remote system as well as on the local system.

Looser coupling
With a synchronous interface the coupling between the client and the server system is too narrow. If the connection is interrupted the client system would not be able to function properly.

Performance
The interface has a large volume of data or database operations to be carried on the server system will take a long time. In this situation a synchronous interface cannot be used because performance would be too low.

BAPI/ALE integration requires that:

	Message types are created and IDoc types are generated for all write BAPIs. See also: Generating the BAPI-ALE Interface
	All IDoc types and the associated segments are released.
	The BAPI interface and the IDoc interface are identical. Make sure that the message type, IDoc type and segments are regenerated, particularly if the BAPI is changed.

All BAPI export parameters with the exception of the return parameter are ignored and are not included in the IDoc type that is generated.

SAP Internal:

If the BAPI is used to integrate different SAP products, you have make the interface information available in the relevant systems. To do this you have to move the data structures (including data elements and domains) used by the BAPI as well as the ALE interface, if necessary, into the application basis.

Provided that the applications involved have restricted usability (componentization, e.g. AC/LO and HR, some R/3 New Dimensions ), the BAPI function module must be explicitly released for cross-application use.

Please consult your BFA contact person.