StreamBase has an internal data structure called a tuple to encapsulate the incoming stream of data. The tuple format is very flexible and can manage both simple name-value pair streams as well as multi-level, hierarchical data streams with multiple levels of subunits.

The format of each tuple is described in a schema in the same way that a database table's structure is described as a schema. The difference with StreamBase schemas is that they can be very complex and multi-level to support incoming data streams that require them.

The schema describes a single unit of the streamed data. Each subsequent unit is expected to find its data fully described by the same schema, even if some portions of the next incoming tuple are left blank or null.

Each schema is organized into one or more named fields. In a name-value pair, one field represents the name portion. Each incoming tuple has its own value for each field.