Rules for Service Mapping
Use
You can create mapping between attributes and operations of application services, business objects and external services.
Operation Mapping Rules
Before mapping service operations, consider the following:
· The structure of remotely persisted objects (RFC and Web services) cannot be changed in Composite Application perspective. You should model your service attributes according to these structures so that you can successfully map the operations and attributes.
● The object ID of the external object must be returned after executing a query operation. This is required by CAF. Verify that the external service you wish to map to a query operation returns the object ID.
● The target operation can be from the application service (not implemented) or a business object with remote persistency.
Recommended Mapping for CRUD Operations
When mapping CRUD operations, refer to the table below.
Operation |
Input Message Attributes |
Output Message Attributes |
Description |
create |
Custom key, mandatory, default, and optional create attributes |
Custom key attributes |
Requires only the absolute minimum of parameters for the object to be created. If you need to include additional parameters, either mark them explicitly as taking part in the create operation or you can do it with the UPDATE operation. If the value of the custom key is generated by the external system, you should map it in the output mapping. |
read |
Custom key attributes |
All attributes |
Requires the custom key attributes so that the external system can identify the object. |
update |
All attributes |
None |
Requires the custom key attributes to identify the object. All other attributes are required because any of them might have been changed. No output is needed because if the operation is not successful, it throws an exception. |
delete |
Key |
None |
Requires the custom key attributes to identify the object. No output is needed because if the operation is not successful, it throws an exception. |
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Default Mapping Values
On the Datasource tab page there is a list of all mappings for the selected operation in the table below the mapping trees. You can set constants, which are assigned to the target attribute if the result of the attribute mapping is a nullvalue.
To do this, enter the constant in the target attribute Fixed Value field. The Is Null checkbox indicates that there is no value in the Fixed Value field. If Is Null is unchecked and the Fixed Value field is empty, an empty string is used as value.
Attribute Mapping Rules
Symbol |
Description |
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You can only perform the following types of mapping: · Input mapping – input parameters are mapped to input parameters. · Output mapping – output parameters are mapped to output parameters. |
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You cannot map input to output or output to input parameters. |
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You can map one attribute to several attributes. |
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You cannot map several attributes to one attribute.
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You can map only simple attributes to simple attributes. |
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You cannot map simple attributes to complex attributes and vice versa. |
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To map complex collections, you need to map at least one of their subattributes. The collection mappings are implicit (automatically created). Once you have an implicit complex collection mapping, the mappings of the subattributes of the collection may not leave it. |
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You cannot map references between business objects (associations). All the associations are stored locally. The references are not displayed as attributes in the operation messages at all. |
More Information