Restrictions for the DATASET Type | Teradata Vantage - 17.05 - Restrictions for the DATASET Type - Teradata Database

Teradata Vantageā„¢ - DATASET Data Type

Advanced SQL Engine
Teradata Database
June 2020
Programming Reference

There are length restrictions for the DATASET type.

A storage format must be specified. If not, the following error is reported:
Failure 3706 Syntax error: STORAGE FORMAT must be specified for the DATASET type.

Storage Format Restrictions

A schema must be specified, depending on the storage format used. A schema may be specified at the following levels:
  • Column level. Specify a schema at the column level if included in the CREATE or ALTER TABLE statement as an attribute of a DATASET data type column AND the schema was previously registered using the CREATE storage_format SCHEMA statement.
  • Instance level. Specify a schema at the instance level if no schema has been specified at a higher level. It can be specified to apply to multiple instances of the data (for example, when batch loading similar data) using the CreateDATASET function.

By default, data is validated against the schema provided for a particular instance. This can result in reduced performance. To disable this validation, set the DBS Control field DisableDATASETValidation to TRUE.

The DATASET data type may not be used as an attribute of a structured UDT or as the base type of a Teradata Distinct UDT or ARRAY type.

The DATASET data type may not be ordered, compared or grouped, so no ordering routine is provided.

Use the DATASET data type like any other CDT data type, except that it cannot be relationally compared. Therefore, it cannot be used in an index definition and cannot be used in comparison expressions. However, a portion of the DATASET instance may be selected out using provided system methods or functions. This portion may be used in a comparison operation within a query if it can be cast from a VARCHAR string to a comparable data type, compared as a VARCHAR, or be representative of another predefined, comparable type. Because the type may not be compared, it is not used for comparison in a SET table.