15.10 - AS ASSIGNMENT - Teradata Database

Teradata Database SQL Data Definition Language Syntax and Examples

prodname
Teradata Database
vrm_release
15.10
created_date
December 2015
category
Programming Reference
featnum
B035-1144-151K

To implicitly invoke the specified cast routine on an assignment operation if both of the following statements are true:

  • The source data type of the assignment is compatible with the source data type of the cast result.
  • The target data types are identical.

Note that an assignment operation is defined to be any of the following operations:

  • INSERT
  • UPDATE
  • parameter passing

You can disable this functionality by means of the DisableImplCastForSysFuncOp DBS Control parameter.

Be very careful if you are performing a REPLACE CAST statement because the system updates the UDTCast dictionary to reflect the value of the AS ASSIGNMENT flag.

Example: Casting Source Data as VARCHAR with an Assignment Operation

The following CREATE CAST request creates a cast operation that converts the source data type euro to the target data type VARCHAR(20) using the method euroString.

The casting routine is defined so it is implicitly invoked on an assignment operation assuming the necessary conditions are met for the assignment (see “AS ASSIGNMENT” in the syntax table for more information).

     CREATE CAST (euro AS VARCHAR(20))
     WITH METHOD SYSUDTLIB.euroString( ) FOR euro
     AS ASSIGNMENT