Installing the UDM | C/C++ UDMs | Teradata Vantage - Installing the UDM - Advanced SQL Engine - Teradata Database

After you write and test a UDM, you can install it on the server.

CREATE METHOD Statement

To identify the file name and location of the source code and install it on the server, use the CREATE METHOD statement.

The method is compiled, linked to the dynamic linked library (DLL or SO) associated with the database in which the method resides, and distributed to all dabase nodes in the system.

Note that all UDMs that are defined in a specific database are linked into a single dynamically linked library.

Default and Temporary Paths

The default and temporary paths that Vantage uses to manage UDMs during creation and execution are the same default and temporary paths that are used for UDFs and external stored procedures. For example, Vantage uses the same temporary directory to compile UDFs, UDMs, and external stored procedures.

For more information on default and temporary paths, see Default and Temporary Paths.

Specifying Source File Locations

The EXTERNAL clause of the CREATE METHOD statement specifies the name and path of the source code file.

CREATE METHOD toInches()
RETURNS FLOAT
FOR meter
EXTERNAL;

CREATE METHOD toInches()
RETURNS FLOAT
FOR meter
EXTERNAL NAME meter_toInches;

CREATE METHOD toInches()
RETURNS FLOAT
FOR meter
EXTERNAL NAME 'CS!toInches!udmsrc/toInches.c!F!meter_toInches';

For more information on CREATE METHOD and the EXTERNAL clause, see Teradata Vantage™ - SQL Data Definition Language Detailed Topics, B035-1184.

Source File Locations for ODBC

If you use ODBC, you can only create UDMs from files that are stored on the server.

Source File Locations for JDBC

Using Teradata Driver for the JDBC Interface, you can create UDMs from files that are located on the Teradata server, or from resources located on the client.

A client-side UDM source file must be available as a resource in the class path. The Teradata JDBC driver can load the resource from the class path and transfer it to the server node without directly accessing the client file system.

Specifying the C/C++ Function Name

In addition to specifying the location of the source code, the EXTERNAL clause in the CREATE METHOD statement identifies the C/C++ function name that appears in the C/C++ function declaration or the function entry name when the C/C++ object is provided instead of the C/C++ source.

CREATE METHOD toInches()
RETURNS FLOAT
FOR meter
EXTERNAL;

CREATE METHOD toInches()
RETURNS FLOAT
FOR meter
EXTERNAL NAME meter_toInches;

CREATE METHOD toInches()
RETURNS FLOAT
FOR meter
EXTERNAL NAME 'CS!toInches!udmsrc/toInches.c!F!meter_toInches';

Specifying Nonstandard Include Files

If a UDM includes a nonstandard header file, the EXTERNAL clause in the CREATE METHOD statement must specify the name and path of the header file.

Consider the following UDM that includes the header file ssn.h:

/*****  C source file name: p_ssn.c  *****/

#define SQL_TEXT Latin_Text
#include <sqltypes_td.h>
#include "ssn.h"

void encrypt( UDT_HANDLE    *personalUdt,
              VARCHAR_LATIN *result,
              char           sqlstate[6])
{
     ...
}

Here is an example of CREATE METHOD that specifies the name and path of the nonstandard header file:

CREATE METHOD encrypt()
RETURNS VARCHAR(64)
FOR personal
EXTERNAL NAME
'CI!ssn!udm_home/ssn.h!CS!encrypt!udm_home/p_ssn.c!F!encrypt';

where:

For more information on installing libraries, see the information about CREATE METHOD in Teradata Vantage™ - SQL Data Definition Language Syntax and Examples, B035-1144.

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