Distinct Data Types

A distinct data type has the same internal structure as some other source data type in the database. The source type can be a built-in or extended data type. What distinguishes a distinct type from its source type are support functions that are defined on the distinct type.

No more than approximately 97 columns of the same table can be DISTINCT of collection data types (SET, LIST, and MULTISET). No more than approximately 195 columns of the same table can be DISTINCT types that are based on BYTE, TEXT, ROW, LVARCHAR, NVARCHAR, or VARCHAR source types. (Here 195 columns is an approximate lower limit that applies to platforms with a 2 Kb base page size. For platforms with a base page size of 4 Kb, such as Windows™ and AIX® systems, the upper limit is approximately 450 columns of these data types.) For more information, see the section DISTINCT data types. See also HCL OneDB™ User-Defined Routines and Data Types Developer's Guide.