Example: Use the SCRIPT Table Operator to Invoke a Python Script - Advanced SQL Engine - Teradata Database

In this example, invoke a Python script file using the SCRIPT table operator. The script mapper.py reads in a line of text input (“Old Macdonald Had A Farm”) and splits the line into individual words, emitting a new row for each word.

An example of the Python script:

#!/usr/bin/python
import sys
# input comes from STDIN (standard input)
for line in sys.stdin:
    # remove leading and trailing whitespace
    line = line.strip()
    # split the line into words
    words = line.split()
    # increase counters
    for word in words:
        # write the results to STDOUT (standard output);
        # what we output here will be the input for the
        # Reduce step, i.e. the input for reducer.py
        #
        # tab-delimited; the trivial word count is 1
print '%s\t%s' % (word, 1)

To install the script, run the following command:

CALL SYSUIF.INSTALL_FILE('mapper', 'mapper.py'
                         'cz!/tmp/mapper.py');

The table barrier contains the sentence as one line of text input:

To split the sentence into individual words, run the following script:

SELECT * FROM SCRIPT
( ON ( SELECT name FROM barrier )	
SCRIPT_COMMAND('./mydb/mapper.py')
	RETURNS ( 'word varchar(10)', 'count_input int' ) ) AS tab;
);

The result: