You must generate the service when you have defined the metadata for it.
You generate the service in the Service Builder, which automatically generates the code for making your service OData compliant, and for use in SAP Gateway.
For more information about OData, go to:http://www.odata.org
In addition, the Service Builder automatically configures the project by assigning the data model to the generated service for use at runtime.
The following occurs when you generate the service:
The implementation classes for the data model and the service are automatically created.
The service is automatically registered in SAP Gateway.
Service Builder automatically generates the corresponding code where you have mapped parameters of a data source to the properties of an entity set.
For more information, see Mapping.
Make sure that you have a properly defined data model, Entity Data Model (EDMX) or metadata (XML) file.