16.20 - tdr.Open - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL External Routine Programming

Product
Advanced SQL Engine
Teradata Database
Release Number
16.20
Release Date
April 2020
Content Type
Programming Reference
Publication ID
B035-1147-162K
Language
English (United States)

Purpose

Opens an input or output stream.

Syntax

tdr.Open(  direction,  streamno,  options  )
direction
Parameter type: character
Valid values are as follows:
  • "R" (input)
  • "W" (output)
streamno
Parameter type: integer

The stream number.

options
Parameter type: integer
How the stream is manipulated.
The only valid value for options is 0, which indicates that individual attributes can be accessed or modified.

Return Value

This function returns one of the following values:
  • A handle to the iterator associated with the stream. The handle is of type raw and can be used to read or write rows and to close the iterator.
  • NULL if an error occurred.

Usage Notes

The function opens an input or output stream. Once the stream is opened, rows can be read or written.

You can open an input stream multiple times within a table operator invocation. Each open resets the read position to the start of the stream. If you specify the PARTITION BY clause, opening a stream refers to the rows within a partition. If you do not specify a PARTITION BY clause, opening a stream refers to the rows within the AMP.

You can open an output stream a single time within a table operator invocation.

This function is valid only if called from the table operator.
The following are not allowed and result in an error:
  • Open an input or output stream that is already open.
  • Close and reopen an output stream.
  • Call this function from the contract function.

Example: Opening an Input Stream

# Open the input stream.
library(tdr);
stream <- 0;
options <- 0;
direction <- "R";
inHandle <- tdr.Open(direction, stream, options);