Function alias, also called function mapping, lets you give a function a name that is more descriptive or easier to use when running the function on a foreign server. You can use a function alias instead of referring to a long name, arguments, or complex function execution methods. A function alias hides the location where the function is run.
In function call query:
SELECT * FROM function_name (..
function_name can refer to an installed function or a function alias. For execution, Advanced SQL Engine first searches for function alias, followed by installed function. The current database of the user is looked up first, followed by globally accessible databases syslib and td_sysfnlib.Use these commands when working with function alias:
| Command | Purpose |
|---|---|
| CREATE FUNCTION MAPPING | Creates a function alias. |
| DROP FUNCTION MAPPING | Drops an existing function alias. |
| REPLACE FUNCTION MAPPING | Changes the function alias definition. |
| SHOW FUNCTION MAPPING | Displays the SQL data definition text for the function alias. |
nPath and Ntree are exceptions. Function aliases are not defined for these two functions. You must append "@coprocessor" to these function names. For example:
SELECT * FROM nPath@coprocessor ( ...
See Teradata Vantage™ - SQL Data Definition Language Syntax and Examples, B035-1144.
For information about function mapping execution, see Teradata Vantage™ - SQL Data Manipulation Language, B035-1146.