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#------------------------------------------------------------------------------
# Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
#------------------------------------------------------------------------------
#------------------------------------------------------------------------------
# query_strings_as_bytes.py
#
# Demonstrates how to query strings as bytes (bypassing decoding of the bytes
# into a Python string). This can be useful when attempting to fetch data that
# was stored in the database in the wrong encoding.
#
# This script requires cx_Oracle 8.2 and higher.
#------------------------------------------------------------------------------
import cx_Oracle as oracledb
import sample_env
STRING_VAL = 'I bought a cafetière on the Champs-Élysées'
def return_strings_as_bytes(cursor, name, default_type, size, precision,
scale):
if default_type == oracledb.DB_TYPE_VARCHAR:
return cursor.var(str, arraysize=cursor.arraysize, bypass_decode=True)
with oracledb.connect(sample_env.get_main_connect_string()) as conn:
# truncate table and populate with our data of choice
with conn.cursor() as cursor:
cursor.execute("truncate table TestTempTable")
cursor.execute("insert into TestTempTable values (1, :val)",
val=STRING_VAL)
conn.commit()
# fetch the data normally and show that it is returned as a string
with conn.cursor() as cursor:
cursor.execute("select IntCol, StringCol from TestTempTable")
print("Data fetched using normal technique:")
for row in cursor:
print(row)
print()
# fetch the data, bypassing the decode and show that it is returned as
# bytes
with conn.cursor() as cursor:
cursor.outputtypehandler = return_strings_as_bytes
cursor.execute("select IntCol, StringCol from TestTempTable")
print("Data fetched using bypass decode technique:")
for row in cursor:
print(row)
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