206 lines
5.6 KiB
ReStructuredText
206 lines
5.6 KiB
ReStructuredText
.. _subscrobj:
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*******************
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Subscription Object
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*******************
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.. note::
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This object is an extension the DB API.
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.. attribute:: Subscription.callback
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This read-only attribute returns the callback that was registered when the
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subscription was created.
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.. attribute:: Subscription.connection
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This read-only attribute returns the connection that was used to register
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the subscription when it was created.
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.. attribute:: Subscription.id
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This read-only attribute returns the registration ID returned by the
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database when the subscription was created.
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.. deprecated:: 6.0
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This attribute was never intended to be exposed.
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.. attribute:: Subscription.namespace
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This read-only attribute returns the namespace used to register the
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subscription when it was created.
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.. attribute:: Subscription.operations
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This read-only attribute returns the operations that will send notifications
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for each table or query that is registered using this subscription.
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.. attribute:: Subscription.port
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This read-only attribute returns the port used for callback notifications
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from the database server. If not set during construction, this value is
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zero.
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.. attribute:: Subscription.protocol
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This read-only attribute returns the protocol used to register the
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subscription when it was created.
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.. attribute:: Subscription.qos
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This read-only attribute returns the quality of service flags used to
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register the subscription when it was created.
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.. method:: Subscription.registerquery(statement, [args])
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Register the query for subsequent notification when tables referenced by the
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query are changed. This behaves similarly to cursor.execute() but only
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queries are permitted and the arguments must be a sequence or dictionary.
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If the qos parameter included the flag cx_Oracle.SUBSCR_QOS_QUERY when
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the subscription was created, then the ID for the registered query is
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returned; otherwise, None is returned.
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.. attribute:: Subscription.timeout
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This read-only attribute returns the timeout (in seconds) that was specified
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when the subscription was created. A value of 0 indicates that there is no
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timeout.
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.. _msgobjects:
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Message Objects
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===============
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.. note::
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This object is created internally when notification is received and passed
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to the callback procedure specified when a subscription is created.
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.. attribute:: Message.dbname
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This read-only attribute returns the name of the database that generated the
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notification.
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.. attribute:: Message.queries
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This read-only attribute returns a list of message query objects that give
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information about query result sets changed for this notification. This
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attribute will be None if the qos parameter did not include the flag
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:data:`~cx_Oracle.SUBSCR_QOS_QUERY` when the subscription was created.
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.. attribute:: Message.subscription
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This read-only attribute returns the subscription object for which this
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notification was generated.
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.. attribute:: Message.tables
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This read-only attribute returns a list of message table objects that give
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information about the tables changed for this notification. This
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attribute will be None if the qos parameter included the flag
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:data:`~cx_Oracle.SUBSCR_QOS_QUERY` when the subscription was created.
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.. attribute:: Message.type
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This read-only attribute returns the type of message that has been sent.
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See the constants section on event types for additional information.
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Message Table Objects
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=====================
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.. note::
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This object is created internally for each table changed when notification
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is received and is found in the tables attribute of message objects, and
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the tables attribute of message query objects.
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.. attribute:: MessageTable.name
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This read-only attribute returns the name of the table that was changed.
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.. attribute:: MessageTable.operation
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This read-only attribute returns the operation that took place on the table
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that was changed.
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.. attribute:: MessageTable.rows
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This read-only attribute returns a list of message row objects that give
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information about the rows changed on the table. This value is only filled
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in if the qos parameter to the :meth:`Connection.subscribe()` method
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included the flag :data:`~cx_Oracle.SUBSCR_QOS_ROWIDS`.
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Message Row Objects
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===================
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.. note::
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This object is created internally for each row changed on a table when
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notification is received and is found in the rows attribute of message table
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objects.
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.. attribute:: MessageRow.operation
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This read-only attribute returns the operation that took place on the row
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that was changed.
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.. attribute:: MessageRow.rowid
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This read-only attribute returns the rowid of the row that was changed.
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Message Query Objects
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=====================
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.. note::
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This object is created internally for each query result set changed when
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notification is received and is found in the queries attribute of message
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objects.
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.. attribute:: MessageQuery.id
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This read-only attribute returns the query id of the query for which the
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result set changed. The value will match the value returned by
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Subscription.registerquery when the related query was registered.
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.. attribute:: MessageQuery.operation
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This read-only attribute returns the operation that took place on the query
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result set that was changed. Valid values for this attribute are
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:data:`~cx_Oracle.EVENT_DEREG` and :data:`~cx_Oracle.EVENT_QUERYCHANGE`.
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.. attribute:: MessageQuery.tables
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This read-only attribute returns a list of message table objects that give
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information about the table changes that caused the query result set to
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change for this notification.
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