16.20 - Teradata Large-objects - Teradata Tools and Utilities

Teradata® Call-Level Interface Version 2 Reference for Mainframe-Attached Systems

Teradata Tools and Utilities
September 2019
Programming Reference

Normal fields in a Teradata database table are limited to 64000 bytes. To allow for significantly larger fields, such as audio or video data, CLIv2 supports large object (LOB) fields. If LOBs exceed the maximum statement size, their data is provided deferred to subsequent requests using the AS DEFERRED phrase in the USING row descriptor for the request string instead of being entirely included in the initial request, such as (USING BLOB AS DEFERRED) or (USING BLOB AS DEFERRED BY NAME). For DEFERRED BY NAME, the name is of data type VARCHAR. In this case, Teradata Database includes an ElicitData or ElicitDataByName parcel in the response to prompt the CLIv2 application to provide data for the LOB. Having been slated for deferral by such a row descriptor, if it happens that a Large-object is small enough to fit into the request, then the DBCAREA LOB-aggregate-data-pointer may address an area that overrides AS DEFERRED by providing that Large-object’s data in the same request.