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Editing: cx_oracle.py
# dialects/oracle/cx_oracle.py # Copyright (C) 2005-2025 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under # the MIT License: https://www.opensource.org/licenses/mit-license.php # mypy: ignore-errors r""".. dialect:: oracle+cx_oracle :name: cx-Oracle :dbapi: cx_oracle :connectstring: oracle+cx_oracle://user:pass@hostname:port[/dbname][?service_name=<service>[&key=value&key=value...]] :url: https://oracle.github.io/python-cx_Oracle/ Description ----------- cx_Oracle was the original driver for Oracle Database. It was superseded by python-oracledb which should be used instead. DSN vs. Hostname connections ----------------------------- cx_Oracle provides several methods of indicating the target database. The dialect translates from a series of different URL forms. Hostname Connections with Easy Connect Syntax ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Given a hostname, port and service name of the target database, for example from Oracle Database's Easy Connect syntax then connect in SQLAlchemy using the ``service_name`` query string parameter:: engine = create_engine( "oracle+cx_oracle://scott:tiger@hostname:port?service_name=myservice&encoding=UTF-8&nencoding=UTF-8" ) Note that the default driver value for encoding and nencoding was changed to “UTF-8” in cx_Oracle 8.0 so these parameters can be omitted when using that version, or later. To use a full Easy Connect string, pass it as the ``dsn`` key value in a :paramref:`_sa.create_engine.connect_args` dictionary:: import cx_Oracle e = create_engine( "oracle+cx_oracle://@", connect_args={ "user": "scott", "password": "tiger", "dsn": "hostname:port/myservice?transport_connect_timeout=30&expire_time=60", }, ) Connections with tnsnames.ora or to Oracle Autonomous Database ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Alternatively, if no port, database name, or service name is provided, the dialect will use an Oracle Database DSN "connection string". This takes the "hostname" portion of the URL as the data source name. For example, if the ``tnsnames.ora`` file contains a TNS Alias of ``myalias`` as below: .. sourcecode:: text myalias = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = mymachine.example.com)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = orclpdb1) ) ) The cx_Oracle dialect connects to this database service when ``myalias`` is the hostname portion of the URL, without specifying a port, database name or ``service_name``:: engine = create_engine("oracle+cx_oracle://scott:tiger@myalias") Users of Oracle Autonomous Database should use this syntax. If the database is configured for mutural TLS ("mTLS"), then you must also configure the cloud wallet as shown in cx_Oracle documentation `Connecting to Autononmous Databases <https://cx-oracle.readthedocs.io/en/latest/user_guide/connection_handling.html#autonomousdb>`_. SID Connections ^^^^^^^^^^^^^^^ To use Oracle Database's obsolete System Identifier connection syntax, the SID can be passed in a "database name" portion of the URL:: engine = create_engine( "oracle+cx_oracle://scott:tiger@hostname:port/dbname" ) Above, the DSN passed to cx_Oracle is created by ``cx_Oracle.makedsn()`` as follows:: >>> import cx_Oracle >>> cx_Oracle.makedsn("hostname", 1521, sid="dbname") '(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=hostname)(PORT=1521))(CONNECT_DATA=(SID=dbname)))' Note that although the SQLAlchemy syntax ``hostname:port/dbname`` looks like Oracle's Easy Connect syntax it is different. It uses a SID in place of the service name required by Easy Connect. The Easy Connect syntax does not support SIDs. Passing cx_Oracle connect arguments ----------------------------------- Additional connection arguments can usually be passed via the URL query string; particular symbols like ``SYSDBA`` are intercepted and converted to the correct symbol:: e = create_engine( "oracle+cx_oracle://user:pass@dsn?encoding=UTF-8&nencoding=UTF-8&mode=SYSDBA&events=true" ) .. versionchanged:: 1.3 the cx_Oracle dialect now accepts all argument names within the URL string itself, to be passed to the cx_Oracle DBAPI. As was the case earlier but not correctly documented, the :paramref:`_sa.create_engine.connect_args` parameter also accepts all cx_Oracle DBAPI connect arguments. To pass arguments directly to ``.connect()`` without using the query string, use the :paramref:`_sa.create_engine.connect_args` dictionary. Any cx_Oracle parameter value and/or constant may be passed, such as:: import cx_Oracle e = create_engine( "oracle+cx_oracle://user:pass@dsn", connect_args={ "encoding": "UTF-8", "nencoding": "UTF-8", "mode": cx_Oracle.SYSDBA, "events": True, }, ) Note that the default driver value for ``encoding`` and ``nencoding`` was changed to "UTF-8" in cx_Oracle 8.0 so these parameters can be omitted when using that version, or later. Options consumed by the SQLAlchemy cx_Oracle dialect outside of the driver -------------------------------------------------------------------------- There are also options that are consumed by the SQLAlchemy cx_oracle dialect itself. These options are always passed directly to :func:`_sa.create_engine` , such as:: e = create_engine( "oracle+cx_oracle://user:pass@dsn", coerce_to_decimal=False ) The parameters accepted by the cx_oracle dialect are as follows: * ``arraysize`` - set the cx_oracle.arraysize value on cursors; defaults to ``None``, indicating that the driver default should be used (typically the value is 100). This setting controls how many rows are buffered when fetching rows, and can have a significant effect on performance when modified. .. versionchanged:: 2.0.26 - changed the default value from 50 to None, to use the default value of the driver itself. * ``auto_convert_lobs`` - defaults to True; See :ref:`cx_oracle_lob`. * ``coerce_to_decimal`` - see :ref:`cx_oracle_numeric` for detail. * ``encoding_errors`` - see :ref:`cx_oracle_unicode_encoding_errors` for detail. .. _cx_oracle_sessionpool: Using cx_Oracle SessionPool --------------------------- The cx_Oracle driver provides its own connection pool implementation that may be used in place of SQLAlchemy's pooling functionality. The driver pool supports Oracle Database features such dead connection detection, connection draining for planned database downtime, support for Oracle Application Continuity and Transparent Application Continuity, and gives support for Database Resident Connection Pooling (DRCP). Using the driver pool can be achieved by using the :paramref:`_sa.create_engine.creator` parameter to provide a function that returns a new connection, along with setting :paramref:`_sa.create_engine.pool_class` to ``NullPool`` to disable SQLAlchemy's pooling:: import cx_Oracle from sqlalchemy import create_engine from sqlalchemy.pool import NullPool pool = cx_Oracle.SessionPool( user="scott", password="tiger", dsn="orclpdb", min=1, max=4, increment=1, threaded=True, encoding="UTF-8", nencoding="UTF-8", ) engine = create_engine( "oracle+cx_oracle://", creator=pool.acquire, poolclass=NullPool ) The above engine may then be used normally where cx_Oracle's pool handles connection pooling:: with engine.connect() as conn: print(conn.scalar("select 1 from dual")) As well as providing a scalable solution for multi-user applications, the cx_Oracle session pool supports some Oracle features such as DRCP and `Application Continuity <https://cx-oracle.readthedocs.io/en/latest/user_guide/ha.html#application-continuity-ac>`_. Note that the pool creation parameters ``threaded``, ``encoding`` and ``nencoding`` were deprecated in later cx_Oracle releases. Using Oracle Database Resident Connection Pooling (DRCP) -------------------------------------------------------- When using Oracle Database's DRCP, the best practice is to pass a connection class and "purity" when acquiring a connection from the SessionPool. Refer to the `cx_Oracle DRCP documentation <https://cx-oracle.readthedocs.io/en/latest/user_guide/connection_handling.html#database-resident-connection-pooling-drcp>`_. This can be achieved by wrapping ``pool.acquire()``:: import cx_Oracle from sqlalchemy import create_engine from sqlalchemy.pool import NullPool pool = cx_Oracle.SessionPool( user="scott", password="tiger", dsn="orclpdb", min=2, max=5, increment=1, threaded=True, encoding="UTF-8", nencoding="UTF-8", ) def creator(): return pool.acquire( cclass="MYCLASS", purity=cx_Oracle.ATTR_PURITY_SELF ) engine = create_engine( "oracle+cx_oracle://", creator=creator, poolclass=NullPool ) The above engine may then be used normally where cx_Oracle handles session pooling and Oracle Database additionally uses DRCP:: with engine.connect() as conn: print(conn.scalar("select 1 from dual")) .. _cx_oracle_unicode: Unicode ------- As is the case for all DBAPIs under Python 3, all strings are inherently Unicode strings. In all cases however, the driver requires an explicit encoding configuration. Ensuring the Correct Client Encoding ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The long accepted standard for establishing client encoding for nearly all Oracle Database related software is via the `NLS_LANG <https://www.oracle.com/database/technologies/faq-nls-lang.html>`_ environment variable. Older versions of cx_Oracle use this environment variable as the source of its encoding configuration. The format of this variable is Territory_Country.CharacterSet; a typical value would be ``AMERICAN_AMERICA.AL32UTF8``. cx_Oracle version 8 and later use the character set "UTF-8" by default, and ignore the character set component of NLS_LANG. The cx_Oracle driver also supported a programmatic alternative which is to pass the ``encoding`` and ``nencoding`` parameters directly to its ``.connect()`` function. These can be present in the URL as follows:: engine = create_engine( "oracle+cx_oracle://scott:tiger@tnsalias?encoding=UTF-8&nencoding=UTF-8" ) For the meaning of the ``encoding`` and ``nencoding`` parameters, please consult `Characters Sets and National Language Support (NLS) <https://cx-oracle.readthedocs.io/en/latest/user_guide/globalization.html#globalization>`_. .. seealso:: `Characters Sets and National Language Support (NLS) <https://cx-oracle.readthedocs.io/en/latest/user_guide/globalization.html#globalization>`_ - in the cx_Oracle documentation. Unicode-specific Column datatypes ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The Core expression language handles unicode data by use of the :class:`.Unicode` and :class:`.UnicodeText` datatypes. These types correspond to the VARCHAR2 and CLOB Oracle Database datatypes by default. When using these datatypes with Unicode data, it is expected that the database is configured with a Unicode-aware character set, as well as that the ``NLS_LANG`` environment variable is set appropriately (this applies to older versions of cx_Oracle), so that the VARCHAR2 and CLOB datatypes can accommodate the data. In the case that Oracle Database is not configured with a Unicode character set, the two options are to use the :class:`_types.NCHAR` and :class:`_oracle.NCLOB` datatypes explicitly, or to pass the flag ``use_nchar_for_unicode=True`` to :func:`_sa.create_engine`, which will cause the SQLAlchemy dialect to use NCHAR/NCLOB for the :class:`.Unicode` / :class:`.UnicodeText` datatypes instead of VARCHAR/CLOB. .. versionchanged:: 1.3 The :class:`.Unicode` and :class:`.UnicodeText` datatypes now correspond to the ``VARCHAR2`` and ``CLOB`` Oracle Database datatypes unless the ``use_nchar_for_unicode=True`` is passed to the dialect when :func:`_sa.create_engine` is called. .. _cx_oracle_unicode_encoding_errors: Encoding Errors ^^^^^^^^^^^^^^^ For the unusual case that data in Oracle Database is present with a broken encoding, the dialect accepts a parameter ``encoding_errors`` which will be passed to Unicode decoding functions in order to affect how decoding errors are handled. The value is ultimately consumed by the Python `decode <https://docs.python.org/3/library/stdtypes.html#bytes.decode>`_ function, and is passed both via cx_Oracle's ``encodingErrors`` parameter consumed by ``Cursor.var()``, as well as SQLAlchemy's own decoding function, as the cx_Oracle dialect makes use of both under different circumstances. .. versionadded:: 1.3.11 .. _cx_oracle_setinputsizes: Fine grained control over cx_Oracle data binding performance with setinputsizes ------------------------------------------------------------------------------- The cx_Oracle DBAPI has a deep and fundamental reliance upon the usage of the DBAPI ``setinputsizes()`` call. The purpose of this call is to establish the datatypes that are bound to a SQL statement for Python values being passed as parameters. While virtually no other DBAPI assigns any use to the ``setinputsizes()`` call, the cx_Oracle DBAPI relies upon it heavily in its interactions with the Oracle Database client interface, and in some scenarios it is not possible for SQLAlchemy to know exactly how data should be bound, as some settings can cause profoundly different performance characteristics, while altering the type coercion behavior at the same time. Users of the cx_Oracle dialect are **strongly encouraged** to read through cx_Oracle's list of built-in datatype symbols at https://cx-oracle.readthedocs.io/en/latest/api_manual/module.html#database-types. Note that in some cases, significant performance degradation can occur when using these types vs. not, in particular when specifying ``cx_Oracle.CLOB``. On the SQLAlchemy side, the :meth:`.DialectEvents.do_setinputsizes` event can be used both for runtime visibility (e.g. logging) of the setinputsizes step as well as to fully control how ``setinputsizes()`` is used on a per-statement basis. .. versionadded:: 1.2.9 Added :meth:`.DialectEvents.setinputsizes` Example 1 - logging all setinputsizes calls ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The following example illustrates how to log the intermediary values from a SQLAlchemy perspective before they are converted to the raw ``setinputsizes()`` parameter dictionary. The keys of the dictionary are :class:`.BindParameter` objects which have a ``.key`` and a ``.type`` attribute:: from sqlalchemy import create_engine, event engine = create_engine("oracle+cx_oracle://scott:tiger@host/xe") @event.listens_for(engine, "do_setinputsizes") def _log_setinputsizes(inputsizes, cursor, statement, parameters, context): for bindparam, dbapitype in inputsizes.items(): log.info( "Bound parameter name: %s SQLAlchemy type: %r DBAPI object: %s", bindparam.key, bindparam.type, dbapitype, ) Example 2 - remove all bindings to CLOB ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The ``CLOB`` datatype in cx_Oracle incurs a significant performance overhead, however is set by default for the ``Text`` type within the SQLAlchemy 1.2 series. This setting can be modified as follows:: from sqlalchemy import create_engine, event from cx_Oracle import CLOB engine = create_engine("oracle+cx_oracle://scott:tiger@host/xe") @event.listens_for(engine, "do_setinputsizes") def _remove_clob(inputsizes, cursor, statement, parameters, context): for bindparam, dbapitype in list(inputsizes.items()): if dbapitype is CLOB: del inputsizes[bindparam] .. _cx_oracle_lob: LOB Datatypes -------------- LOB datatypes refer to the "large object" datatypes such as CLOB, NCLOB and BLOB. Modern versions of cx_Oracle is optimized for these datatypes to be delivered as a single buffer. As such, SQLAlchemy makes use of these newer type handlers by default. To disable the use of newer type handlers and deliver LOB objects as classic buffered objects with a ``read()`` method, the parameter ``auto_convert_lobs=False`` may be passed to :func:`_sa.create_engine`, which takes place only engine-wide. .. _cx_oracle_returning: RETURNING Support ----------------- The cx_Oracle dialect implements RETURNING using OUT parameters. The dialect supports RETURNING fully. Two Phase Transactions Not Supported ------------------------------------ Two phase transactions are **not supported** under cx_Oracle due to poor driver support. The newer :ref:`oracledb` dialect however **does** support two phase transactions. .. _cx_oracle_numeric: Precision Numerics ------------------ SQLAlchemy's numeric types can handle receiving and returning values as Python ``Decimal`` objects or float objects. When a :class:`.Numeric` object, or a subclass such as :class:`.Float`, :class:`_oracle.DOUBLE_PRECISION` etc. is in use, the :paramref:`.Numeric.asdecimal` flag determines if values should be coerced to ``Decimal`` upon return, or returned as float objects. To make matters more complicated under Oracle Database, the ``NUMBER`` type can also represent integer values if the "scale" is zero, so the Oracle Database-specific :class:`_oracle.NUMBER` type takes this into account as well. The cx_Oracle dialect makes extensive use of connection- and cursor-level "outputtypehandler" callables in order to coerce numeric values as requested. These callables are specific to the specific flavor of :class:`.Numeric` in use, as well as if no SQLAlchemy typing objects are present. There are observed scenarios where Oracle Database may send incomplete or ambiguous information about the numeric types being returned, such as a query where the numeric types are buried under multiple levels of subquery. The type handlers do their best to make the right decision in all cases, deferring to the underlying cx_Oracle DBAPI for all those cases where the driver can make the best decision. When no typing objects are present, as when executing plain SQL strings, a default "outputtypehandler" is present which will generally return numeric values which specify precision and scale as Python ``Decimal`` objects. To disable this coercion to decimal for performance reasons, pass the flag ``coerce_to_decimal=False`` to :func:`_sa.create_engine`:: engine = create_engine("oracle+cx_oracle://dsn", coerce_to_decimal=False) The ``coerce_to_decimal`` flag only impacts the results of plain string SQL statements that are not otherwise associated with a :class:`.Numeric` SQLAlchemy type (or a subclass of such). .. versionchanged:: 1.2 The numeric handling system for cx_Oracle has been reworked to take advantage of newer cx_Oracle features as well as better integration of outputtypehandlers. """ # noqa from __future__ import annotations import decimal import random import re from . import base as oracle from .base import OracleCompiler from .base import OracleDialect from .base import OracleExecutionContext from .types import _OracleDateLiteralRender from ... import exc from ... import util from ...engine import cursor as _cursor from ...engine import interfaces from ...engine import processors from ...sql import sqltypes from ...sql._typing import is_sql_compiler # source: # https://github.com/oracle/python-cx_Oracle/issues/596#issuecomment-999243649 _CX_ORACLE_MAGIC_LOB_SIZE = 131072 class _OracleInteger(sqltypes.Integer): def get_dbapi_type(self, dbapi): # see https://github.com/oracle/python-cx_Oracle/issues/ # 208#issuecomment-409715955 return int def _cx_oracle_var(self, dialect, cursor, arraysize=None): cx_Oracle = dialect.dbapi return cursor.var( cx_Oracle.STRING, 255, arraysize=arraysize if arraysize is not None else cursor.arraysize, outconverter=int, ) def _cx_oracle_outputtypehandler(self, dialect): def handler(cursor, name, default_type, size, precision, scale): return self._cx_oracle_var(dialect, cursor) return handler class _OracleNumeric(sqltypes.Numeric): is_number = False def bind_processor(self, dialect): if self.scale == 0: return None elif self.asdecimal: processor = processors.to_decimal_processor_factory( decimal.Decimal, self._effective_decimal_return_scale ) def process(value): if isinstance(value, (int, float)): return processor(value) elif value is not None and value.is_infinite(): return float(value) else: return value return process else: return processors.to_float def result_processor(self, dialect, coltype): return None def _cx_oracle_outputtypehandler(self, dialect): cx_Oracle = dialect.dbapi def handler(cursor, name, default_type, size, precision, scale): outconverter = None if precision: if self.asdecimal: if default_type == cx_Oracle.NATIVE_FLOAT: # receiving float and doing Decimal after the fact # allows for float("inf") to be handled type_ = default_type outconverter = decimal.Decimal else: type_ = decimal.Decimal else: if self.is_number and scale == 0: # integer. cx_Oracle is observed to handle the widest # variety of ints when no directives are passed, # from 5.2 to 7.0. See [ticket:4457] return None else: type_ = cx_Oracle.NATIVE_FLOAT else: if self.asdecimal: if default_type == cx_Oracle.NATIVE_FLOAT: type_ = default_type outconverter = decimal.Decimal else: type_ = decimal.Decimal else: if self.is_number and scale == 0: # integer. cx_Oracle is observed to handle the widest # variety of ints when no directives are passed, # from 5.2 to 7.0. See [ticket:4457] return None else: type_ = cx_Oracle.NATIVE_FLOAT return cursor.var( type_, 255, arraysize=cursor.arraysize, outconverter=outconverter, ) return handler class _OracleUUID(sqltypes.Uuid): def get_dbapi_type(self, dbapi): return dbapi.STRING class _OracleBinaryFloat(_OracleNumeric): def get_dbapi_type(self, dbapi): return dbapi.NATIVE_FLOAT class _OracleBINARY_FLOAT(_OracleBinaryFloat, oracle.BINARY_FLOAT): pass class _OracleBINARY_DOUBLE(_OracleBinaryFloat, oracle.BINARY_DOUBLE): pass class _OracleNUMBER(_OracleNumeric): is_number = True class _CXOracleDate(oracle._OracleDate): def bind_processor(self, dialect): return None def result_processor(self, dialect, coltype): def process(value): if value is not None: return value.date() else: return value return process class _CXOracleTIMESTAMP(_OracleDateLiteralRender, sqltypes.TIMESTAMP): def literal_processor(self, dialect): return self._literal_processor_datetime(dialect) class _LOBDataType: pass # TODO: the names used across CHAR / VARCHAR / NCHAR / NVARCHAR # here are inconsistent and not very good class _OracleChar(sqltypes.CHAR): def get_dbapi_type(self, dbapi): return dbapi.FIXED_CHAR class _OracleNChar(sqltypes.NCHAR): def get_dbapi_type(self, dbapi): return dbapi.FIXED_NCHAR class _OracleUnicodeStringNCHAR(oracle.NVARCHAR2): def get_dbapi_type(self, dbapi): return dbapi.NCHAR class _OracleUnicodeStringCHAR(sqltypes.Unicode): def get_dbapi_type(self, dbapi): return dbapi.LONG_STRING class _OracleUnicodeTextNCLOB(_LOBDataType, oracle.NCLOB): def get_dbapi_type(self, dbapi): # previously, this was dbapi.NCLOB. # DB_TYPE_NVARCHAR will instead be passed to setinputsizes() # when this datatype is used. return dbapi.DB_TYPE_NVARCHAR class _OracleUnicodeTextCLOB(_LOBDataType, sqltypes.UnicodeText): def get_dbapi_type(self, dbapi): # previously, this was dbapi.CLOB. # DB_TYPE_NVARCHAR will instead be passed to setinputsizes() # when this datatype is used. return dbapi.DB_TYPE_NVARCHAR class _OracleText(_LOBDataType, sqltypes.Text): def get_dbapi_type(self, dbapi): # previously, this was dbapi.CLOB. # DB_TYPE_NVARCHAR will instead be passed to setinputsizes() # when this datatype is used. return dbapi.DB_TYPE_NVARCHAR class _OracleLong(_LOBDataType, oracle.LONG): def get_dbapi_type(self, dbapi): return dbapi.LONG_STRING class _OracleString(sqltypes.String): pass class _OracleEnum(sqltypes.Enum): def bind_processor(self, dialect): enum_proc = sqltypes.Enum.bind_processor(self, dialect) def process(value): raw_str = enum_proc(value) return raw_str return process class _OracleBinary(_LOBDataType, sqltypes.LargeBinary): def get_dbapi_type(self, dbapi): # previously, this was dbapi.BLOB. # DB_TYPE_RAW will instead be passed to setinputsizes() # when this datatype is used. return dbapi.DB_TYPE_RAW def bind_processor(self, dialect): return None def result_processor(self, dialect, coltype): if not dialect.auto_convert_lobs: return None else: return super().result_processor(dialect, coltype) class _OracleInterval(oracle.INTERVAL): def get_dbapi_type(self, dbapi): return dbapi.INTERVAL class _OracleRaw(oracle.RAW): pass class _OracleRowid(oracle.ROWID): def get_dbapi_type(self, dbapi): return dbapi.ROWID class OracleCompiler_cx_oracle(OracleCompiler): _oracle_cx_sql_compiler = True _oracle_returning = False # Oracle bind names can't start with digits or underscores. # currently we rely upon Oracle-specific quoting of bind names in most # cases. however for expanding params, the escape chars are used. # see #8708 bindname_escape_characters = util.immutabledict( { "%": "P", "(": "A", ")": "Z", ":": "C", ".": "C", "[": "C", "]": "C", " ": "C", "\\": "C", "/": "C", "?": "C", } ) def bindparam_string(self, name, **kw): quote = getattr(name, "quote", None) if ( quote is True or quote is not False and self.preparer._bindparam_requires_quotes(name) # bind param quoting for Oracle doesn't work with post_compile # params. For those, the default bindparam_string will escape # special chars, and the appending of a number "_1" etc. will # take care of reserved words and not kw.get("post_compile", False) ): # interesting to note about expanding parameters - since the # new parameters take the form <paramname>_<int>, at least if # they are originally formed from reserved words, they no longer # need quoting :). names that include illegal characters # won't work however. quoted_name = '"%s"' % name kw["escaped_from"] = name name = quoted_name return OracleCompiler.bindparam_string(self, name, **kw) # TODO: we could likely do away with quoting altogether for # Oracle parameters and use the custom escaping here escaped_from = kw.get("escaped_from", None) if not escaped_from: if self._bind_translate_re.search(name): # not quite the translate use case as we want to # also get a quick boolean if we even found # unusual characters in the name new_name = self._bind_translate_re.sub( lambda m: self._bind_translate_chars[m.group(0)], name, ) if new_name[0].isdigit() or new_name[0] == "_": new_name = "D" + new_name kw["escaped_from"] = name name = new_name elif name[0].isdigit() or name[0] == "_": new_name = "D" + name kw["escaped_from"] = name name = new_name return OracleCompiler.bindparam_string(self, name, **kw) class OracleExecutionContext_cx_oracle(OracleExecutionContext): out_parameters = None def _generate_out_parameter_vars(self): # check for has_out_parameters or RETURNING, create cx_Oracle.var # objects if so if self.compiled.has_out_parameters or self.compiled._oracle_returning: out_parameters = self.out_parameters assert out_parameters is not None len_params = len(self.parameters) quoted_bind_names = self.compiled.escaped_bind_names for bindparam in self.compiled.binds.values(): if bindparam.isoutparam: name = self.compiled.bind_names[bindparam] type_impl = bindparam.type.dialect_impl(self.dialect) if hasattr(type_impl, "_cx_oracle_var"): out_parameters[name] = type_impl._cx_oracle_var( self.dialect, self.cursor, arraysize=len_params ) else: dbtype = type_impl.get_dbapi_type(self.dialect.dbapi) cx_Oracle = self.dialect.dbapi assert cx_Oracle is not None if dbtype is None: raise exc.InvalidRequestError( "Cannot create out parameter for " "parameter " "%r - its type %r is not supported by" " cx_oracle" % (bindparam.key, bindparam.type) ) # note this is an OUT parameter. Using # non-LOB datavalues with large unicode-holding # values causes the failure (both cx_Oracle and # oracledb): # ORA-22835: Buffer too small for CLOB to CHAR or # BLOB to RAW conversion (actual: 16507, # maximum: 4000) # [SQL: INSERT INTO long_text (x, y, z) VALUES # (:x, :y, :z) RETURNING long_text.x, long_text.y, # long_text.z INTO :ret_0, :ret_1, :ret_2] # so even for DB_TYPE_NVARCHAR we convert to a LOB if isinstance(type_impl, _LOBDataType): if dbtype == cx_Oracle.DB_TYPE_NVARCHAR: dbtype = cx_Oracle.NCLOB elif dbtype == cx_Oracle.DB_TYPE_RAW: dbtype = cx_Oracle.BLOB # other LOB types go in directly out_parameters[name] = self.cursor.var( dbtype, # this is fine also in oracledb_async since # the driver will await the read coroutine outconverter=lambda value: value.read(), arraysize=len_params, ) elif ( isinstance(type_impl, _OracleNumeric) and type_impl.asdecimal ): out_parameters[name] = self.cursor.var( decimal.Decimal, arraysize=len_params, ) else: out_parameters[name] = self.cursor.var( dbtype, arraysize=len_params ) for param in self.parameters: param[quoted_bind_names.get(name, name)] = ( out_parameters[name] ) def _generate_cursor_outputtype_handler(self): output_handlers = {} for keyname, name, objects, type_ in self.compiled._result_columns: handler = type_._cached_custom_processor( self.dialect, "cx_oracle_outputtypehandler", self._get_cx_oracle_type_handler, ) if handler: denormalized_name = self.dialect.denormalize_name(keyname) output_handlers[denormalized_name] = handler if output_handlers: default_handler = self._dbapi_connection.outputtypehandler def output_type_handler( cursor, name, default_type, size, precision, scale ): if name in output_handlers: return output_handlers[name]( cursor, name, default_type, size, precision, scale ) else: return default_handler( cursor, name, default_type, size, precision, scale ) self.cursor.outputtypehandler = output_type_handler def _get_cx_oracle_type_handler(self, impl): if hasattr(impl, "_cx_oracle_outputtypehandler"): return impl._cx_oracle_outputtypehandler(self.dialect) else: return None def pre_exec(self): super().pre_exec() if not getattr(self.compiled, "_oracle_cx_sql_compiler", False): return self.out_parameters = {} self._generate_out_parameter_vars() self._generate_cursor_outputtype_handler() def post_exec(self): if ( self.compiled and is_sql_compiler(self.compiled) and self.compiled._oracle_returning ): initial_buffer = self.fetchall_for_returning( self.cursor, _internal=True ) fetch_strategy = _cursor.FullyBufferedCursorFetchStrategy( self.cursor, [ (entry.keyname, None) for entry in self.compiled._result_columns ], initial_buffer=initial_buffer, ) self.cursor_fetch_strategy = fetch_strategy def create_cursor(self): c = self._dbapi_connection.cursor() if self.dialect.arraysize: c.arraysize = self.dialect.arraysize return c def fetchall_for_returning(self, cursor, *, _internal=False): compiled = self.compiled if ( not _internal and compiled is None or not is_sql_compiler(compiled) or not compiled._oracle_returning ): raise NotImplementedError( "execution context was not prepared for Oracle RETURNING" ) # create a fake cursor result from the out parameters. unlike # get_out_parameter_values(), the result-row handlers here will be # applied at the Result level numcols = len(self.out_parameters) # [stmt_result for stmt_result in outparam.values] == each # statement in executemany # [val for val in stmt_result] == each row for a particular # statement return list( zip( *[ [ val for stmt_result in self.out_parameters[ f"ret_{j}" ].values for val in (stmt_result or ()) ] for j in range(numcols) ] ) ) def get_out_parameter_values(self, out_param_names): # this method should not be called when the compiler has # RETURNING as we've turned the has_out_parameters flag set to # False. assert not self.compiled.returning return [ self.dialect._paramval(self.out_parameters[name]) for name in out_param_names ] class OracleDialect_cx_oracle(OracleDialect): supports_statement_cache = True execution_ctx_cls = OracleExecutionContext_cx_oracle statement_compiler = OracleCompiler_cx_oracle supports_sane_rowcount = True supports_sane_multi_rowcount = True insert_executemany_returning = True insert_executemany_returning_sort_by_parameter_order = True update_executemany_returning = True delete_executemany_returning = True bind_typing = interfaces.BindTyping.SETINPUTSIZES driver = "cx_oracle" colspecs = util.update_copy( OracleDialect.colspecs, { sqltypes.TIMESTAMP: _CXOracleTIMESTAMP, sqltypes.Numeric: _OracleNumeric, sqltypes.Float: _OracleNumeric, oracle.BINARY_FLOAT: _OracleBINARY_FLOAT, oracle.BINARY_DOUBLE: _OracleBINARY_DOUBLE, sqltypes.Integer: _OracleInteger, oracle.NUMBER: _OracleNUMBER, sqltypes.Date: _CXOracleDate, sqltypes.LargeBinary: _OracleBinary, sqltypes.Boolean: oracle._OracleBoolean, sqltypes.Interval: _OracleInterval, oracle.INTERVAL: _OracleInterval, sqltypes.Text: _OracleText, sqltypes.String: _OracleString, sqltypes.UnicodeText: _OracleUnicodeTextCLOB, sqltypes.CHAR: _OracleChar, sqltypes.NCHAR: _OracleNChar, sqltypes.Enum: _OracleEnum, oracle.LONG: _OracleLong, oracle.RAW: _OracleRaw, sqltypes.Unicode: _OracleUnicodeStringCHAR, sqltypes.NVARCHAR: _OracleUnicodeStringNCHAR, sqltypes.Uuid: _OracleUUID, oracle.NCLOB: _OracleUnicodeTextNCLOB, oracle.ROWID: _OracleRowid, }, ) execute_sequence_format = list _cx_oracle_threaded = None _cursor_var_unicode_kwargs = util.immutabledict() @util.deprecated_params( threaded=( "1.3", "The 'threaded' parameter to the cx_oracle/oracledb dialect " "is deprecated as a dialect-level argument, and will be removed " "in a future release. As of version 1.3, it defaults to False " "rather than True. The 'threaded' option can be passed to " "cx_Oracle directly in the URL query string passed to " ":func:`_sa.create_engine`.", ) ) def __init__( self, auto_convert_lobs=True, coerce_to_decimal=True, arraysize=None, encoding_errors=None, threaded=None, **kwargs, ): OracleDialect.__init__(self, **kwargs) self.arraysize = arraysize self.encoding_errors = encoding_errors if encoding_errors: self._cursor_var_unicode_kwargs = { "encodingErrors": encoding_errors } if threaded is not None: self._cx_oracle_threaded = threaded self.auto_convert_lobs = auto_convert_lobs self.coerce_to_decimal = coerce_to_decimal if self._use_nchar_for_unicode: self.colspecs = self.colspecs.copy() self.colspecs[sqltypes.Unicode] = _OracleUnicodeStringNCHAR self.colspecs[sqltypes.UnicodeText] = _OracleUnicodeTextNCLOB dbapi_module = self.dbapi self._load_version(dbapi_module) if dbapi_module is not None: # these constants will first be seen in SQLAlchemy datatypes # coming from the get_dbapi_type() method. We then # will place the following types into setinputsizes() calls # on each statement. Oracle constants that are not in this # list will not be put into setinputsizes(). self.include_set_input_sizes = { dbapi_module.DATETIME, dbapi_module.DB_TYPE_NVARCHAR, # used for CLOB, NCLOB dbapi_module.DB_TYPE_RAW, # used for BLOB dbapi_module.NCLOB, # not currently used except for OUT param dbapi_module.CLOB, # not currently used except for OUT param dbapi_module.LOB, # not currently used dbapi_module.BLOB, # not currently used except for OUT param dbapi_module.NCHAR, dbapi_module.FIXED_NCHAR, dbapi_module.FIXED_CHAR, dbapi_module.TIMESTAMP, int, # _OracleInteger, # _OracleBINARY_FLOAT, _OracleBINARY_DOUBLE, dbapi_module.NATIVE_FLOAT, } self._paramval = lambda value: value.getvalue() def _load_version(self, dbapi_module): version = (0, 0, 0) if dbapi_module is not None: m = re.match(r"(\d+)\.(\d+)(?:\.(\d+))?", dbapi_module.version) if m: version = tuple( int(x) for x in m.group(1, 2, 3) if x is not None ) self.cx_oracle_ver = version if self.cx_oracle_ver < (8,) and self.cx_oracle_ver > (0, 0, 0): raise exc.InvalidRequestError( "cx_Oracle version 8 and above are supported" ) @classmethod def import_dbapi(cls): import cx_Oracle return cx_Oracle def initialize(self, connection): super().initialize(connection) self._detect_decimal_char(connection) def get_isolation_level(self, dbapi_connection): # sources: # general idea of transaction id, have to start one, etc. # https://stackoverflow.com/questions/10711204/how-to-check-isoloation-level # how to decode xid cols from v$transaction to match # https://asktom.oracle.com/pls/apex/f?p=100:11:0::::P11_QUESTION_ID:9532779900346079444 # Oracle tuple comparison without using IN: # https://www.sql-workbench.eu/comparison/tuple_comparison.html with dbapi_connection.cursor() as cursor: # this is the only way to ensure a transaction is started without # actually running DML. There's no way to see the configured # isolation level without getting it from v$transaction which # means transaction has to be started. outval = cursor.var(str) cursor.execute( """ begin :trans_id := dbms_transaction.local_transaction_id( TRUE ); end; """, {"trans_id": outval}, ) trans_id = outval.getvalue() xidusn, xidslot, xidsqn = trans_id.split(".", 2) cursor.execute( "SELECT CASE BITAND(t.flag, POWER(2, 28)) " "WHEN 0 THEN 'READ COMMITTED' " "ELSE 'SERIALIZABLE' END AS isolation_level " "FROM v$transaction t WHERE " "(t.xidusn, t.xidslot, t.xidsqn) = " "((:xidusn, :xidslot, :xidsqn))", {"xidusn": xidusn, "xidslot": xidslot, "xidsqn": xidsqn}, ) row = cursor.fetchone() if row is None: raise exc.InvalidRequestError( "could not retrieve isolation level" ) result = row[0] return result def get_isolation_level_values(self, dbapi_connection): return super().get_isolation_level_values(dbapi_connection) + [ "AUTOCOMMIT" ] def set_isolation_level(self, dbapi_connection, level): if level == "AUTOCOMMIT": dbapi_connection.autocommit = True else: dbapi_connection.autocommit = False dbapi_connection.rollback() with dbapi_connection.cursor() as cursor: cursor.execute(f"ALTER SESSION SET ISOLATION_LEVEL={level}") def _detect_decimal_char(self, connection): # we have the option to change this setting upon connect, # or just look at what it is upon connect and convert. # to minimize the chance of interference with changes to # NLS_TERRITORY or formatting behavior of the DB, we opt # to just look at it dbapi_connection = connection.connection with dbapi_connection.cursor() as cursor: # issue #8744 # nls_session_parameters is not available in some Oracle # modes like "mount mode". But then, v$nls_parameters is not # available if the connection doesn't have SYSDBA priv. # # simplify the whole thing and just use the method that we were # doing in the test suite already, selecting a number def output_type_handler( cursor, name, defaultType, size, precision, scale ): return cursor.var( self.dbapi.STRING, 255, arraysize=cursor.arraysize ) cursor.outputtypehandler = output_type_handler cursor.execute("SELECT 1.1 FROM DUAL") value = cursor.fetchone()[0] decimal_char = value.lstrip("0")[1] assert not decimal_char[0].isdigit() self._decimal_char = decimal_char if self._decimal_char != ".": _detect_decimal = self._detect_decimal _to_decimal = self._to_decimal self._detect_decimal = lambda value: _detect_decimal( value.replace(self._decimal_char, ".") ) self._to_decimal = lambda value: _to_decimal( value.replace(self._decimal_char, ".") ) def _detect_decimal(self, value): if "." in value: return self._to_decimal(value) else: return int(value) _to_decimal = decimal.Decimal def _generate_connection_outputtype_handler(self): """establish the default outputtypehandler established at the connection level. """ dialect = self cx_Oracle = dialect.dbapi number_handler = _OracleNUMBER( asdecimal=True )._cx_oracle_outputtypehandler(dialect) float_handler = _OracleNUMBER( asdecimal=False )._cx_oracle_outputtypehandler(dialect) def output_type_handler( cursor, name, default_type, size, precision, scale ): if ( default_type == cx_Oracle.NUMBER and default_type is not cx_Oracle.NATIVE_FLOAT ): if not dialect.coerce_to_decimal: return None elif precision == 0 and scale in (0, -127): # ambiguous type, this occurs when selecting # numbers from deep subqueries return cursor.var( cx_Oracle.STRING, 255, outconverter=dialect._detect_decimal, arraysize=cursor.arraysize, ) elif precision and scale > 0: return number_handler( cursor, name, default_type, size, precision, scale ) else: return float_handler( cursor, name, default_type, size, precision, scale ) # if unicode options were specified, add a decoder, otherwise # cx_Oracle should return Unicode elif ( dialect._cursor_var_unicode_kwargs and default_type in ( cx_Oracle.STRING, cx_Oracle.FIXED_CHAR, ) and default_type is not cx_Oracle.CLOB and default_type is not cx_Oracle.NCLOB ): return cursor.var( str, size, cursor.arraysize, **dialect._cursor_var_unicode_kwargs, ) elif dialect.auto_convert_lobs and default_type in ( cx_Oracle.CLOB, cx_Oracle.NCLOB, ): typ = ( cx_Oracle.DB_TYPE_VARCHAR if default_type is cx_Oracle.CLOB else cx_Oracle.DB_TYPE_NVARCHAR ) return cursor.var( typ, _CX_ORACLE_MAGIC_LOB_SIZE, cursor.arraysize, **dialect._cursor_var_unicode_kwargs, ) elif dialect.auto_convert_lobs and default_type in ( cx_Oracle.BLOB, ): return cursor.var( cx_Oracle.DB_TYPE_RAW, _CX_ORACLE_MAGIC_LOB_SIZE, cursor.arraysize, ) return output_type_handler def on_connect(self): output_type_handler = self._generate_connection_outputtype_handler() def on_connect(conn): conn.outputtypehandler = output_type_handler return on_connect def create_connect_args(self, url): opts = dict(url.query) for opt in ("use_ansi", "auto_convert_lobs"): if opt in opts: util.warn_deprecated( f"{self.driver} dialect option {opt!r} should only be " "passed to create_engine directly, not within the URL " "string", version="1.3", ) util.coerce_kw_type(opts, opt, bool) setattr(self, opt, opts.pop(opt)) database = url.database service_name = opts.pop("service_name", None) if database or service_name: # if we have a database, then we have a remote host port = url.port if port: port = int(port) else: port = 1521 if database and service_name: raise exc.InvalidRequestError( '"service_name" option shouldn\'t ' 'be used with a "database" part of the url' ) if database: makedsn_kwargs = {"sid": database} if service_name: makedsn_kwargs = {"service_name": service_name} dsn = self.dbapi.makedsn(url.host, port, **makedsn_kwargs) else: # we have a local tnsname dsn = url.host if dsn is not None: opts["dsn"] = dsn if url.password is not None: opts["password"] = url.password if url.username is not None: opts["user"] = url.username if self._cx_oracle_threaded is not None: opts.setdefault("threaded", self._cx_oracle_threaded) def convert_cx_oracle_constant(value): if isinstance(value, str): try: int_val = int(value) except ValueError: value = value.upper() return getattr(self.dbapi, value) else: return int_val else: return value util.coerce_kw_type(opts, "mode", convert_cx_oracle_constant) util.coerce_kw_type(opts, "threaded", bool) util.coerce_kw_type(opts, "events", bool) util.coerce_kw_type(opts, "purity", convert_cx_oracle_constant) return ([], opts) def _get_server_version_info(self, connection): return tuple(int(x) for x in connection.connection.version.split(".")) def is_disconnect(self, e, connection, cursor): (error,) = e.args if isinstance( e, (self.dbapi.InterfaceError, self.dbapi.DatabaseError) ) and "not connected" in str(e): return True if hasattr(error, "code") and error.code in { 28, 3114, 3113, 3135, 1033, 2396, }: # ORA-00028: your session has been killed # ORA-03114: not connected to ORACLE # ORA-03113: end-of-file on communication channel # ORA-03135: connection lost contact # ORA-01033: ORACLE initialization or shutdown in progress # ORA-02396: exceeded maximum idle time, please connect again # TODO: Others ? return True if re.match(r"^(?:DPI-1010|DPI-1080|DPY-1001|DPY-4011)", str(e)): # DPI-1010: not connected # DPI-1080: connection was closed by ORA-3113 # python-oracledb's DPY-1001: not connected to database # python-oracledb's DPY-4011: the database or network closed the # connection # TODO: others? return True return False def create_xid(self): id_ = random.randint(0, 2**128) return (0x1234, "%032x" % id_, "%032x" % 9) def do_executemany(self, cursor, statement, parameters, context=None): if isinstance(parameters, tuple): parameters = list(parameters) cursor.executemany(statement, parameters) def do_begin_twophase(self, connection, xid): connection.connection.begin(*xid) connection.connection.info["cx_oracle_xid"] = xid def do_prepare_twophase(self, connection, xid): result = connection.connection.prepare() connection.info["cx_oracle_prepared"] = result def do_rollback_twophase( self, connection, xid, is_prepared=True, recover=False ): self.do_rollback(connection.connection) # TODO: need to end XA state here def do_commit_twophase( self, connection, xid, is_prepared=True, recover=False ): if not is_prepared: self.do_commit(connection.connection) else: if recover: raise NotImplementedError( "2pc recovery not implemented for cx_Oracle" ) oci_prepared = connection.info["cx_oracle_prepared"] if oci_prepared: self.do_commit(connection.connection) # TODO: need to end XA state here def do_set_input_sizes(self, cursor, list_of_tuples, context): if self.positional: # not usually used, here to support if someone is modifying # the dialect to use positional style cursor.setinputsizes( *[dbtype for key, dbtype, sqltype in list_of_tuples] ) else: collection = ( (key, dbtype) for key, dbtype, sqltype in list_of_tuples if dbtype ) cursor.setinputsizes(**{key: dbtype for key, dbtype in collection}) def do_recover_twophase(self, connection): raise NotImplementedError( "recover two phase query for cx_Oracle not implemented" ) dialect = OracleDialect_cx_oracle
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