1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
|
# typecast.py - example of per-cursor and per-connection typecasters.
#
# Copyright (C) 2001-2010 Federico Di Gregorio <fog@debian.org>
#
# psycopg2 is free software: you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# psycopg2 is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser 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]
|
