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# copy_to.py -- example about copy_to
#
# Copyright (C) 2002 Tom Jenkins <tjenkins@devis.com>
# Copyright (C) 2005 Federico Di Gregorio <fog@initd.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
# for more details.
#
## put in DSN your DSN string
DSN = 'dbname=test'
## don't modify anything below tis line (except for experimenting)
import sys
import os
import StringIO
import psycopg2
if len(sys.argv) > 1:
DSN = sys.argv[1]
print "Opening connection using dns:", DSN
conn = psycopg2.connect(DSN)
print "Encoding for this connection is", conn.encoding
curs = conn.cursor()
try:
curs.execute("CREATE TABLE test_copy (fld1 text, fld2 text, fld3 int4)")
except:
conn.rollback()
curs.execute("DROP TABLE test_copy")
curs.execute("CREATE TABLE test_copy (fld1 text, fld2 text, fld3 int4)")
conn.commit()
# demostrate copy_to functionality
data = [('Tom', 'Jenkins', '37'),
('Madonna', None, '45'),
('Federico', 'Di Gregorio', None)]
query = "INSERT INTO test_copy VALUES (%s, %s, %s)"
curs.executemany(query, data)
conn.commit()
# copy_to using defaults
io = open('copy_to.txt', 'w')
curs.copy_to(io, 'test_copy')
print "1) Copy %d records into file object using defaults: " % len (data) + \
"sep = \\t and null = \\N"
io.close()
rows = open('copy_to.txt', 'r').readlines()
print " File has %d rows:" % len(rows)
for r in rows:
print " ", r,
# copy_to using custom separator
io = open('copy_to.txt', 'w')
curs.copy_to(io, 'test_copy', ':')
print "2) Copy %d records into file object using sep = :" % len(data)
io.close()
rows = open('copy_to.txt', 'r').readlines()
print " File has %d rows:" % len(rows)
for r in rows:
print " ", r,
# copy_to using custom null identifier
io = open('copy_to.txt', 'w')
curs.copy_to(io, 'test_copy', null='NULL')
print "3) Copy %d records into file object using null = NULL" % len(data)
io.close()
rows = open('copy_to.txt', 'r').readlines()
print " File has %d rows:" % len(rows)
for r in rows:
print " ", r,
# copy_to using custom separator and null identifier
io = open('copy_to.txt', 'w')
curs.copy_to(io, 'test_copy', ':', 'NULL')
print "4) Copy %d records into file object using sep = : and null ) NULL" % \
len(data)
io.close()
rows = open('copy_to.txt', 'r').readlines()
print " File has %d rows:" % len(rows)
for r in rows:
print " ", r,
curs.execute("DROP TABLE test_copy")
os.unlink('copy_to.txt')
conn.commit()
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