TIME-to-UDT Conversion - Teradata Database

TIME-to-UDT Conversion

Purpose

Converts TIME data to UDT data.

CAST Syntax

where:

Syntax element …	Specifies …
time_expression	a TIME expression to be cast to a UDT.
UDT_data_definition	the UDT type, followed by any optional FORMAT, NAMED, or TITLE data attribute phrases, to which time_expression is to be converted.

ANSI Compliance

This is ANSI SQL:2011 compliant.

As an extension to ANSI, CAST permits the use of data attribute phrases such as FORMAT.

Usage Notes

Explicit TIME-to-UDT conversion using Teradata conversion syntax is not supported.

Data type conversions involving UDTs require appropriate cast definitions for the UDTs. To define a cast for a UDT, use the CREATE CAST statement. For more information on CREATE CAST, see SQL Data Definition Language.

Implicit TIME-to-UDT Conversion

Teradata Database performs implicit TIME-to-UDT conversions for the following operations:

UPDATE

INSERT

Passing arguments to stored procedures, external stored procedures, UDFs, and UDMs

Specific system operators and functions identified in other sections of this book, unless the DisableUDTImplCastForSysFuncOp field of the DBS Control Record is set to TRUE

Performing an implicit data type conversion requires that an appropriate cast definition (see “Usage Notes”) exists that specifies the AS ASSIGNMENT clause.

If no TIME-to-UDT implicit cast definition exists, Teradata Database looks for a CHAR-to-UDT or VARCHAR-to-UDT implicit cast definition that can substitute for the TIME-to-UDT implicit cast definition. Substitutions are valid because Teradata Database can implicitly cast a TIME type to the character data type, and then use the implicit cast definition to cast from the character data type to the UDT. If multiple character-to-UDT implicit cast definitions exist, then Teradata Database returns an SQL error.

Related Topics

For details on data types and data attributes, see SQL Data Types and Literals.