python-cx_Oracle/doc/src/whatsnew.rst
Anthony Tuininga effbb09e09 Correct links.
2018-08-08 16:17:54 -06:00

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.. _whatsnew:
**********
What's New
**********
.. _whatsnew60:
cx_Oracle 6.0
=============
This document contains a summary of the changes in cx_Oracle 6 compared to
cx_Oracle 5.3. cx_Oracle 6.0 was released on August 14, 2017. See the
:ref:`release notes <releasenotes60>` for complete details.
Highlights
----------
- Has been re-implemented to use the new
`ODPI-C <https://oracle.github.io/odpi>`__ abstraction layer for Oracle
Database. The cx_Oracle API is unchanged. The cx_Oracle design, build and
linking process has improved because of ODPI-C.
- Now has Python Wheels available for install. This is made possible by the
ODPI-C architecture. Windows installers and Linux RPMs are no longer
produced since PyPI no longer supports them.
- Has less code in Python's Global Interpreter Lock, giving better
scalability.
- Added support for universal rowids.
- Added support for DML returning of multiple rows.
- Now associates LOB locators to LOB objects so they are not overwritten on
database round trips.
Installation Changes
--------------------
- On Linux, cx_Oracle 6 no longer uses instant client RPMs automatically.
You must set LD_LIBRARY_PATH or use ldconfig to locate the Oracle Client
library.
- On platforms other than Windows, if ORACLE_HOME is set (in a database or
full client installation), remove requirement to set LD_LIBRARY_PATH in
order to locate the Oracle Client library
(`issue 20 <https://github.com/oracle/odpi/issues/20>`__).
Connection Management Enhancements
----------------------------------
- Prevent closing the connection when there are any open statements or LOBs
and add new error "DPI-1054: connection cannot be closed when open
statements or LOBs exist" when this situation is detected; this is needed
to prevent crashes under certain conditions when statements or LOBs are
being acted upon while at the same time (in another thread) a connection
is being closed; it also prevents leaks of statements and LOBs when a
connection is returned to a session pool.
- Added attribute :attr:`SessionPool.stmtcachesize` to support getting and
setting the default statement cache size for connections in the pool.
- Added attribute :attr:`Connection.dbop` to support setting the database
operation that is to be monitored.
- Added attribute :attr:`Connection.handle` to facilitate testing the
creation of a connection using a OCI service context handle.
- Added parameters tag and matchanytag to the :meth:`cx_Oracle.connect` and
:meth:`SessionPool.acquire` methods and added parameters tag and retag to
the :meth:`SessionPool.release` method in order to support session
tagging.
- Added parameter edition to the :meth:`cx_Oracle.SessionPool` method.
- Added parameters region, sharding_key and super_sharding_key to the
:meth:`cx_Oracle.makedsn()` method to support connecting to a sharded
database (new in Oracle Database 12.2).
- Removed requirement that encoding and nencoding both be specified when
creating a connection or session pool. The missing value is set to its
default value if one of the values is set and the other is not
(`issue 36 <https://github.com/oracle/python-cx_Oracle/issues/36>`__).
- Permit use of both string and unicode for Python 2.7 for creating session
pools and for changing passwords
(`issue 23 <https://github.com/oracle/python-cx_Oracle/issues/23>`__).
Data Type and Data Handling Enhancements
----------------------------------------
- Added attributes :attr:`Variable.actualElements` and
:attr:`Variable.values` to variables.
- Added support for smallint and float data types in Oracle objects, as
requested
(`issue 4 <https://github.com/oracle/python-cx_Oracle/issues/4>`__).
- Added support for getting/setting attributes of objects or element values
in collections that contain LOBs, BINARY_FLOAT values, BINARY_DOUBLE
values and NCHAR and NVARCHAR2 values. The error message for any types
that are not supported has been improved as well.
- An exception is no longer raised when a collection is empty for methods
:meth:`Object.first()` and :meth:`Object.last()`. Instead, the value None
is returned to be consistent with the methods :meth:`Object.next()` and
:meth:`Object.prev()`.
- Removed requirement for specifying a maximum size when fetching LONG or
LONG raw columns. This also allows CLOB, NCLOB, BLOB and BFILE columns to
be fetched as strings or bytes without needing to specify a maximum size.
The method :meth:`Cursor.setoutputsize` no longer does anything, since
ODPI-C automatically manages buffer sizes of LONG and LONG RAW columns.
- Enable temporary LOB caching in order to avoid disk I/O as suggested
(`issue 10 <https://github.com/oracle/odpi/issues/10>`__).
Error Handling Enhancements
---------------------------
- Provide improved error message when OCI environment cannot be created,
such as when the oraaccess.xml file cannot be processed properly.
- Define exception classes on the connection object in addition to at
module scope in order to simplify error handling in multi-connection
environments, as specified in the Python DB API.
Test Enhancements
-----------------
- Reworked test suite and samples so that they are independent of each
other and so that the SQL scripts used to create/drop schemas are easily
adjusted to use different schema names, if desired.
- Updated DB API test suite stub to support Python 3.
Removals
--------
- Dropped deprecated parameter twophase from the :meth:`cx_Oracle.connect`
method. Applications should set the :attr:`Connection.internal_name` and
:attr:`Connection.external_name` attributes instead to a value
appropriate to the application.
- Dropped deprecated parameters action, module and clientinfo from the
:meth:`cx_Oracle.connect` method. The appcontext parameter should be used
instead as shown in this `sample <https://github.com/oracle/
python-cx_Oracle/blob/master/samples/AppContext.py>`__.
- Dropped deprecated attribute numbersAsString from
:ref:`cursor objects <cursorobj>`. Use an output type handler instead as
shown in this `sample <https://github.com/oracle/python-cx_Oracle/blob/
master/samples/ReturnNumbersAsDecimals.py>`__.
- Dropped deprecated attributes cqqos and rowids from
:ref:`subscription objects <subscrobj>`. Use the qos attribute instead as
shown in this `sample <https://github.com/oracle/python-cx_Oracle/blob/
master/samples/CQN.py>`__.
- Dropped deprecated parameters cqqos and rowids from the
:meth:`Connection.subscribe()` method. Use the qos parameter instead as
shown in this `sample <https://github.com/oracle/python-cx_Oracle/blob/
master/samples/CQN.py>`__.