When you create a distinct UDT, Teradata Database creates all of the objects or definitions listed as Yes under the Mandatory? column in the following table to enable the full functionality of the type.
|Functionality||Defining DDL Statement||Purpose||Mandatory?|
|Definition of a structured UDT.||CREATE TYPE (Structured Form)||Declares the body and attributes of a structured UDT.||Yes|
|Definition of an instance method.||CREATE METHOD||Declares any SQL-invoked instance methods to be associated with the structured UDT.||No|
|Definition of the ordering for comparing structured UDT values.||CREATE ORDERING||Registers the UDF or method to be used as an ordering routine to compare the structured UDT value with other values.||Yes|
|Declaration of the external ordering routine referenced by CREATE ORDERING.||
||Declares the ordering routine referenced in the CREATE ORDERING definition.||Yes|
|Transformation of a UDT between client and server data types in both directions.||CREATE TRANSFORM||Registers the UDF and UDF or method to be used as a tosql() and fromsql() transform routine to pass the structured UDF in both directions between the client and server.||Yes|
|Declaration of the external transformation routine referenced by CREATE TRANSFORM.||
||Declares the tosql() and fromsql() external routines referenced in the CREATE TRANSFORM definition.||Yes|
|Registration of an external UDF or method casting routine.||CREATE CAST||Registers a UDF or method to be used as a casting routine to cast:
A pair of implicit casts is necessary to achieve full functionality for a distinct UDT: one that casts from the UDT to its fromsql transform target type and one that casts from its tosql transform source type to the UDT. Any additional cast definitions are optional.
|Declaration of the external casting routine referenced by CREATE CAST.||
||Declares the external casting routine referenced in the CREATE CAST statement.||No|