psycopg2/examples/typecast.py
2007-02-22 15:16:54 +00:00

68 lines
2.0 KiB
Python

# typecast.py - example of per-cursor and per-connection typecasters.
#
# Copyright (C) 2001-2007 Federico Di Gregorio <fog@debian.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 this line (except for experimenting)
class SimpleQuoter(object):
def sqlquote(x=None):
return "'bar'"
import sys
import psycopg2
import psycopg2.extensions
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()
curs.execute("SELECT 'text'::text AS foo")
textoid = curs.description[0][1]
print "Oid for the text datatype is", textoid
def castA(s, curs):
if s is not None: return "(A) " + s
TYPEA = psycopg2.extensions.new_type((textoid,), "TYPEA", castA)
def castB(s, curs):
if s is not None: return "(B) " + s
TYPEB = psycopg2.extensions.new_type((textoid,), "TYPEB", castB)
curs = conn.cursor()
curs.execute("SELECT 'some text.'::text AS foo")
print "Some text from plain connection:", curs.fetchone()[0]
psycopg2.extensions.register_type(TYPEA, conn)
curs = conn.cursor()
curs.execute("SELECT 'some text.'::text AS foo")
print "Some text from connection with typecaster:", curs.fetchone()[0]
curs = conn.cursor()
psycopg2.extensions.register_type(TYPEB, curs)
curs.execute("SELECT 'some text.'::text AS foo")
print "Some text from cursor with typecaster:", curs.fetchone()[0]
curs = conn.cursor()
curs.execute("SELECT 'some text.'::text AS foo")
print "Some text from connection with typecaster again:", curs.fetchone()[0]