Get the Fields Available for Retrieval
To identify what kind of information is returned on a Retrieve call for an object, get the fields that are available for that object.
The Retrievemethod takes a list of properties to retrieve on a given object. To build a dynamic list of retrievable properties, use the Describe call and filter out the retrievable fields using the IsRetrievable property.
Use the Describe method when building your integration. However, don't use this call before every Retrieve call. These values are fairly static, so it isn’t necessary to retrieve them frequently.
This sample SOAP envelope shows how to retrieve information about the fields for the SentEvent object.
The response contains the names, data types, and other information about the fields in the specified object.