16.20 - Example: All Castings For A UDT That Has A Single Casting Pair - Teradata Database - Teradata Vantage NewSQL Engine

Teradata Vantage™ SQL Data Definition Language Detailed Topics

Teradata Database
Teradata Vantage NewSQL Engine
Release Number
March 2019
Content Type
Programming Reference
Publication ID
English (United States)

The following example reports both the source and target castings for the UDT named address:

     HELP CAST address;

Source       Target           Cast Routine           As Assignment
address      VARCHAR(80)      address_2_char             YES
VARCHAR(80)  address          char_2_address             YES
Note the following things about this report:
  • The castings from address to VARCHAR(80) and from VARCHAR(80) to address are complementary to one another.
  • Both casting routines are user-defined, which you can tell because neither is named System.
  • This UDT has only one casting pair defined for it, neither of which is named System, which suggests that it is probably a structured type.

    Castings for structured types are never system-generated, while the system always generates default casts for distinct types. Because it is also possible to drop the system-generated casts for a distinct UDT and replace them with user-defined casts, the inference that the casting reported in this example is for a structured UDT cannot be made with certainty. See CREATE CAST and REPLACE CAST for details