15.00 - External Types - FastLoad

Teradata FastLoad Reference

Programming Reference

External Types

The “from‑sql routine” and the “to‑sql routine” create a mapping between a UDT and a pre‑defined type. This pre‑defined type is called the external type of a UDT. A client application only deals with the external type; it does not deal with UDT value directly.

External Type Example

For example, if the following conditions exist:

  • UDT named FULLNAME exists
  • The external type associated with FULLNAME is VARCHAR(46)
  • Then, during an retrieve of FULLNAME values, the Teradata Database server converts the values from FULLNAME values to VARCHAR(46) values by invoking the “from‑sql routine” associated with the FULLNAME UDT.

    Note: The client must expect to receive the data in the same format as it receives VARCHAR(46) values.

    Similarly, when values are provided by the client for insert into a FULLNAME UDT, the client must provide values in the same way it would provide values for a VARCHAR(46) field. The Teradata Database server will convert the values from VARCHAR(46) to FULLNAME values using the “to‑sql routine” associated with the FULLNAME UDT.