在 SAS 隐式 Sql Pass Thru 中使用 Teradata UDF

Question

I am trying to use a Teradata UDF (User Defined Function) in a SAS Implicit SQL which establishes the connection to Teradata using LIBNAME Statement.Assume that the function is called PTY_DECRYPT and is defined in a Database called TEST in Teradata. The Purpose of this function is to decrypt values in a Column of a View in Teradata.

What works is using the UDF in an Explicit Sql .Below I am using the function on a column called SSN_NBR in a view called V_TEST_PERS present in the Database called SAMPLE.

Explcit Sql:

Options  debug=DBMS_TIMERS sastrace=',,,d'
sastraceloc=saslog no$stsuffix fullstimer;


Proc Sql;
Connect to TERADATA(User=XXXXX pwd=XXXXX server=XXXXX);
Create Table Final as
select  *  from connection to teradata
(
Select
sub_id, 
SSN_NBR,
TEST.PTY_DECRYPT(SSN_NBR,'T_ssn_test',400,0,0 ) as SSN_NBR_Decrypt
from SAMPLE.V_TEST_PERS
);
disconnect from teradata;
Quit;

But I would like to use the same function in an Implicit SQL but it does not work. Any ideas as to how to make it work in an Implicit Sql with minimum changes to the Implicit SQL?

Implicit Sql

Options  debug=DBMS_TIMERS sastrace=',,,d'
sastraceloc=saslog no$stsuffix fullstimer;

Libname Td Teradata  User=XXXXX pwd=XXXXX server=XXXXX database=SAMPLE ;

Proc sql;
Create  table Final as
select
sub_id, 
SSN_NBR,
TEST.PTY_DECRYPT(SSN_NBR,'T_ssn_test',400,0,0 ) as SSN_NBR_Decrypt

from Td.V_TEST_PERS;
Quit;

Answer 1

In your implicit SQL you reference the view with the LIBNAME alias TD , however when you reference the UDF you are not aliasing the TEST database containing the UDF with the LIBNAME alias. Syntactically, you may not be able to do that in SAS. (eg TD.TEST.PTY_DECRYPT() - in fact I wouldn't expect this to work)

The UDF may need to be placed in SYSLIB or TD_SYSFNLIB so that it is in a default search path for the database optimizer to find the UDF without being fully qualified. (eg TD_WEEK_BEGIN() ) Alternatively, the UDF could be placed in database SAMPLE but that likely violates how UDFs are maintained in your environment, as it would in my environment.

Otherwise, the UDF call could be embedded in a view on the database, but then you have other issues to consider with the security of that column if your environment is not granting security on a column level basis to views containing encrypted data elements. (eg PHI, PII, etc.) Without a row-column level security mechanism in place to dynamically filter a users ability to see the column you are decrypting in the view putting the UDF into the view isn't going to work.

Answer 2

I asked the same question the SAS Communities Forum and I am glad to say that i did find a Solution to this Problem.

Please see the link below :

https://communities.sas.com/t5/Base-SAS-Programming/Using-a-Teradata-UDF-in-SAS-Implicit-Sql-Pass-Thru/mp/266850/highlight/false#M52685