A message type comprises a data type that describes the structure of a message. For technical reasons, a data type alone is not sufficient to describe the instance of a message: Data types are defined in XML Schema as abstract types that are not yet tied to an element. You can only describe an instance of a message when you have specified a data type as an element type. Therefore, a message type defines the root element of a message.
You can use message types in the following scenarios:
Operations of service interfaces can use the same message type. For example, both an asynchronous operation of an inbound service interface and an asynchronous operation of an outbound service interface can reference the same message type.
Integration Using the Integration Server (A2A, B2B, Web Service)
When you define a message mapping, you can reference message types directly to map messages to each other.
A message type does not define the direction of the message exchange, in other words, whether it is a request or a response. In exceptional cases you can use the same message type for both the request and the response message.
You have already created a data type that you want to reference from your message type.
A message type has the following characteristics:
● It comprises exactly one data type, which determines the content of the message to be transferred.
● It is identified by a name and an XML namespace. The name (together with the namespace) of a message type is located in the uppermost tag of the exchanged message: This tag is of type Element.
You have defined a message type GreetingRes that references a simple data type of type xsd:string. The XML namespace of the message type is http://sap.com/xi/myExample. The corresponding payload might look as follows:
<?xml version="1.0" encoding="utf-8" ?>
Hello Mrs. Miller
You can specify how a message type is used in more detail in the description.
1. Create a message type on the design maintenance screen of the Integration Builder (see also: Creating an Object).
2. Enter a description for your message type.
3. The default setting for XML Namespace is the Repository namespace. If the message type has been copied to another namespace, overwrite the default setting.
4. Reference a data type, either by entering the corresponding name and namespace of the data type in the frame Data Type, or by using input help.
5. Save your changes.
In the example below, two operations from different service interfaces each use the same message type for the request message and the response message: