An External Stored Procedure is written in a language other than SQL, and is defined by the ANSI SQL: 1999 standard. ODBC support of Teradata Database External Stored Procedures (XSP) is transparent to the ODBC user, and should have no effect on existing user applications.
The full specification of the syntax, format, and rules for both creating and invoking XSPs is beyond the scope of this document. See SQL External Routine Programming for details on how to create and invoke user-defined functions.
XSPs are similar to UDFs except the CALL statement is used in the same manner as a stored procedure to invoke an XSP.
The ability to create a XSP function with the XSP source located on the client is restricted. If you try to create a XSP from source on the client, a message will be returned indicating XSPs created from source on the client are not supported.