Multi-Mappings in SAP XI

Use

A multi-mapping is a mapping program that is not restricted to the transformation of one source message to one target message. You have the following options:

• You can use a multi-mapping in a transformation step in a integration process. In this case, the mapping runtime supports 1:n-, n:1, and n:m transformations. You can map any number of source messages to any number of target messages.
• You can use a multi-mapping to map a message to multiple different (and generally smaller) messages during logical routing. Only a 1:n transformation is possible in this case.

Integration

As is the case for all mapping programs, to be able to configure the mapping programs for source and target interfaces, you need to assign a multi-mapping program to an interface mapping that you will use later in the Integration Directory.

Processing Multi-Mappings at Runtime

Multi-mappings reference multiple message structures. To map these structures to one another, the mapping runtime gathers all the source messages of one multi-mapping in one source structure and all the target messages of one multi-mapping in one target structure. This means that instead of trying to map multiple messages to each other, you only have a source structure being mapped to a target structure.

Example

You can generally implement a multi-mapping with all types of mapping program. For simplicity, the following section assumes that you want to implement a multi-mapping as a message mapping.

Imagine the following are message types that you want to map to each other:

Message Types for the Source Structure

Message Type (Source Structure)	Message Type (Target Structure)
OrderHeader (1)	Order (1)
OrderItem (0..unbounded)	OrderInfo (1)

You can specify these message types on the Messages tab page in the mapping editor. You can also specify an occurrence rate for each message type. If the source or target structure can comprise multiple messages, the mapping editor creates a sub-structure for both the source and the target structure in which the source and target messages are stored. The root element is always in a case like this. The mapping editor inserts an element N> for each source or target message, where N is the position of the message according to the Messages tab page. A message instance for the message specified above looks as follows:

There is a N> element for each message schema (for each message type here). The message type can occur unbounded in the message instance as a sub-element of . The numbers specify which elements in the multi-mapping are mapped to each other.

At runtime, the message instances are collected in an integration process and then put in a structure. Once the mapping program has been executed, they are transferred to various message instances again.

Features

If you specify multiple source or target messages in the mapping editor, the mapping editor immediately displays the source or target structure described above in the structure overview. The mapping editor supports the following message schemata for multi-mappings:

· (Fault) message types

· IDocs, RFCs (request-, response, or fault messages), see Importing IDocs and RFCs

· Message structures from external definitions

You can also develop multi-mappings as external mapping programs by exporting the message schema of the request message from an interface mapping.

See also:

Developing Multi-Mappings for Integration Processes

Developing Multi-Mappings for Message Splits