A "Tuple Descriptor" stores information about the schema of a stream and information about the schema of the rows in the stream. Adapters written using certain Sybase CEP SDKs use a Tuple Descriptor to help the adapter work properly with the stream.
A Tuple Descriptor is created by compiling a file that contains the schema definition.
Tuple Descriptors are documented in more detail later in the manual, when we document how to publish and subscribe to streams.