cqn.py

# -----------------------------------------------------------------------------
# Copyright (c) 2016, 2023, Oracle and/or its affiliates.
#
# Portions Copyright 2007-2015, Anthony Tuininga. All rights reserved.
#
# Portions Copyright 2001-2007, Computronix (Canada) Ltd., Edmonton, Alberta,
# Canada. All rights reserved.
#
# This software is dual-licensed to you under the Universal Permissive License
# (UPL) 1.0 as shown at https://oss.oracle.com/licenses/upl and Apache License
# 2.0 as shown at http://www.apache.org/licenses/LICENSE-2.0. You may choose
# either license.
#
# If you elect to accept the software under the Apache License, Version 2.0,
# the following applies:
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# -----------------------------------------------------------------------------

# -----------------------------------------------------------------------------
# cqn.py
#
# Demonstrates using continuous query notification in Python, a feature that is
# available in Oracle 11g and later. Once this script is running, use another
# session to insert, update or delete rows from the table TestTempTable and you
# will see the notification of that change.
# -----------------------------------------------------------------------------

importtime

importoracledb
importsample_env

# this script is currently only supported in python-oracledb thick mode
oracledb.init_oracle_client(lib_dir=sample_env.get_oracle_client())

registered=True


defcallback(message):
globalregistered
print("Message type:", message.type)
ifnotmessage.registered:
print("Deregistration has taken place...")
registered=False
return
print("Message database name:", message.dbname)
print("Message transaction id:", message.txid)
print("Message queries:")
forqueryinmessage.queries:
print("--> Query ID:", query.id)
print("--> Query Operation:", query.operation)
fortableinquery.tables:
print("--> --> Table Name:", table.name)
print("--> --> Table Operation:", table.operation)
iftable.rowsisnotNone:
print("--> --> Table Rows:")
forrowintable.rows:
print("--> --> --> Row RowId:", row.rowid)
print("--> --> --> Row Operation:", row.operation)
print("-"*60)
print("="*60)


connection=oracledb.connect(
user=sample_env.get_main_user(),
password=sample_env.get_main_password(),
dsn=sample_env.get_connect_string(),
events=True,
)

qos=oracledb.SUBSCR_QOS_QUERY|oracledb.SUBSCR_QOS_ROWIDS
sub=connection.subscribe(
callback=callback, timeout=1800, qos=qos, client_initiated=True
)
print("Subscription:", sub)
print("--> Connection:", sub.connection)
print("--> Callback:", sub.callback)
print("--> Namespace:", sub.namespace)
print("--> Protocol:", sub.protocol)
print("--> Timeout:", sub.timeout)
print("--> Operations:", sub.operations)
print("--> Rowids?:", bool(sub.qos&oracledb.SUBSCR_QOS_ROWIDS))
query_id=sub.registerquery("select * from TestTempTable")
print("Registered query:", query_id)

whileregistered:
print("Waiting for notifications....")
time.sleep(5)