Path Filtering Using a Key in the Path | NOS | Teradata Vantage - 17.10 - Path Filtering Using a Key in the Path of the Data Set - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - Native Object Store Getting Started Guide

Advanced SQL Engine
Teradata Database
Release Number
Release Date
July 2021
Content Type
Programming Reference
Publication ID
English (United States)

Key (or path) filtering reduces the number of external objects that are transferred to provide the result. This reduces the I/O performed on the external object store time and results in less work for the SQL Engine.

The examples and results show a sample river flow data set. To use your own data, replace the table and column names, and authorization object.

  1. To run NOS-related commands, log on to the database as a user with the required privileges.
  2. Create a foreign table or ask your database administrator to create the foreign table specifying a LOCATION that filters on site_no. Use the authorization object created in Controlling Foreign Table Access with an AUTHORIZATION Object:
    SELECT TOP 2 columnX, columnY
    FROM table_name
    WHERE $path.columnN = value;

Example: Path Filtering Using a Key in the Path of the Data Set

If not already done, create the foreign table. See Filtering Using a Path Filter in the CREATE FOREIGN TABLE Definition.

SELECT TOP 2 GageHeight, Flow
FROM riverflow_pathfilter
WHERE $path.$site_no = 09396100;

Your result will be similar to the following:

GageHeight  Flow
----------  -----
1.06        6.82
0.49        0