text: # oracle/cx_oracle.py
  # Copyright (C) 2005-2017 the SQLAlchemy authors and contributors
  # <see AUTHORS file>
  #
  # This module is part of SQLAlchemy and is released under
  # the MIT License: http://www.opensource.org/licenses/mit-license.php
  
  """
  
  .. dialect:: oracle+cx_oracle
      :name: cx-Oracle
      :dbapi: cx_oracle
      :connectstring: oracle+cx_oracle://user:pass@host:port/dbname\
  [?key=value&key=value...]
      :url: http://cx-oracle.sourceforge.net/
  
  Additional Connect Arguments
  ----------------------------
  
  When connecting with ``dbname`` present, the host, port, and dbname tokens are
  converted to a TNS name using
  the cx_oracle ``makedsn()`` function.  Otherwise, the host token is taken
  directly as a TNS name.
  
  Additional arguments which may be specified either as query string arguments
  on the URL, or as keyword arguments to :func:`.create_engine()` are:
  
  * ``arraysize`` - set the cx_oracle.arraysize value on cursors, defaulted
    to 50.  This setting is significant with cx_Oracle as the contents of LOB
    objects are only readable within a "live" row (e.g. within a batch of
    50 rows).
  
  * ``auto_convert_lobs`` - defaults to True; See :ref:`cx_oracle_lob`.
  
  * ``coerce_to_unicode`` - see :ref:`cx_oracle_unicode` for detail.
  
  * ``coerce_to_decimal`` - see :ref:`cx_oracle_numeric` for detail.
  
  * ``mode`` - This is given the string value of SYSDBA or SYSOPER, or
    alternatively an integer value.  This value is only available as a URL query
    string argument.
  
  * ``threaded`` - enable multithreaded access to cx_oracle connections.
    Defaults to ``True``.  Note that this is the opposite default of the
    cx_Oracle DBAPI itself.
  
  * ``service_name`` - An option to use connection string (DSN) with
    ``SERVICE_NAME`` instead of ``SID``. It can't be passed when a ``database``
    part is given.
    E.g. ``oracle+cx_oracle://scott:tiger@host:1521/?service_name=hr``
    is a valid url. This value is only available as a URL query string argument.
  
    .. versionadded:: 1.0.0
  
  .. _cx_oracle_unicode:
  
  Unicode
  -------
  
  The cx_Oracle DBAPI as of version 5 fully supports unicode, and has the
  ability to return string results as Python unicode objects natively.
  
  When used in Python 3, cx_Oracle returns all strings as Python unicode objects
  (that is, plain ``str`` in Python 3).  In Python 2, it will return as Python
  unicode those column values that are of type ``NVARCHAR`` or ``NCLOB``.  For
  column values that are of type ``VARCHAR`` or other non-unicode string types,
  it will return values as Python strings (e.g. bytestrings).
  
  The cx_Oracle SQLAlchemy dialect presents several different options for the use
  case of receiving ``VARCHAR`` column values as Python unicode objects under
  Python 2:
  
  * When using Core expression objects as well as the ORM, SQLAlchemy's
    unicode-decoding services are available, which are established by
    using either the :class:`.Unicode` datatype or by using the
    :class:`.String` datatype with :paramref:`.String.convert_unicode` set
    to True.
  
  * When using raw SQL strings, typing behavior can be added for unicode
    conversion using the :func:`.text` construct::
  
      from sqlalchemy import text, Unicode
      result = conn.execute(
          text("select username from user").columns(username=Unicode))
  
  * Otherwise, when using raw SQL strings sent directly to an ``.execute()``
    method without any Core typing behavior added, the flag
    ``coerce_to_unicode=True`` flag can be passed to :func:`.create_engine`
    which will add an unconditional unicode processor to cx_Oracle for all
    string values::
  
      engine = create_engine("oracle+cx_oracle://dsn", coerce_to_unicode=True)
  
    The above approach will add significant latency to result-set fetches
    of plain string values.
  
  
  .. _cx_oracle_returning:
  
  RETURNING Support
  -----------------
  
  The cx_Oracle dialect implements RETURNING using OUT parameters.
  The dialect supports RETURNING fully, however cx_Oracle 6 is recommended
  for complete support.
  
  .. _cx_oracle_lob:
  
  LOB Objects
  -----------
  
  cx_oracle returns oracle LOBs using the cx_oracle.LOB object.  SQLAlchemy
  converts these to strings so that the interface of the Binary type is
  consistent with that of other backends, which takes place within a cx_Oracle
  outputtypehandler.
  
  cx_Oracle prior to version 6 would require that LOB objects be read before
  a new batch of rows would be read, as determined by the ``cursor.arraysize``.
  As of the 6 series, this limitation has been lifted.  Nevertheless, because
  SQLAlchemy pre-reads these LOBs up front, this issue is avoided in any case.
  
  To disable the auto "read()" feature of the dialect, the flag
  ``auto_convert_lobs=False`` may be passed to :func:`.create_engine`.  Under
  the cx_Oracle 5 series, having this flag turned off means there is the chance
  of reading from a stale LOB object if not read as it is fetched.   With
  cx_Oracle 6, this issue is resolved.
  
  .. versionchanged:: 1.2  the LOB handling system has been greatly simplified
     internally to make use of outputtypehandlers, and no longer makes use
     of alternate "buffered" result set objects.
  
  Two Phase Transactions Not Supported
  -------------------------------------
  
  Two phase transactions are **not supported** under cx_Oracle due to poor
  driver support.   As of cx_Oracle 6.0b1, the interface for
  two phase transactions has been changed to be more of a direct pass-through
  to the underlying OCI layer with less automation.  The additional logic
  to support this system is not implemented in SQLAlchemy.
  
  .. _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, Oracle's ``NUMBER`` type can also
  represent integer values if the "scale" is zero, so the Oracle-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 may sends 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:`.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 staements 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.
  
  """
  
  from __future__ import absolute_import
  
  from .base import OracleCompiler, OracleDialect, OracleExecutionContext
  from . import base as oracle
  from ...engine import result as _result
  from sqlalchemy import types as sqltypes, util, exc, processors
  import random
  import collections
  import decimal
  import re
  import time
  
  
  class _OracleInteger(sqltypes.Integer):
      def _cx_oracle_var(self, dialect, cursor):
          cx_Oracle = dialect.dbapi
          return cursor.var(
              cx_Oracle.STRING,
              255,
              arraysize=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)
                  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
  
          is_cx_oracle_6 = dialect._is_cx_oracle_6
          has_native_int = dialect._has_native_int
  
          def handler(cursor, name, default_type, size, precision, scale):
              outconverter = None
              if precision:
                  if self.asdecimal:
                      if is_cx_oracle_6:
                          type_ = decimal.Decimal
                      else:
                          type_ = cx_Oracle.STRING
                          outconverter = dialect._to_decimal
                  else:
                      if self.is_number and scale == 0:
                          if has_native_int:
                              type_ = cx_Oracle.NATIVE_INT
                          else:
                              type_ = cx_Oracle.NUMBER
                              outconverter = int
                      else:
                          type_ = cx_Oracle.NATIVE_FLOAT
              else:
                  if self.asdecimal:
                      if is_cx_oracle_6:
                          type_ = decimal.Decimal
                      else:
                          type_ = cx_Oracle.STRING
                          outconverter = dialect._to_decimal
                  else:
                      if self.is_number and scale == 0:
                          if has_native_int:
                              type_ = cx_Oracle.NATIVE_INT
                          else:
                              type_ = cx_Oracle.NUMBER
                              outconverter = int
                      else:
                          type_ = cx_Oracle.NATIVE_FLOAT
  
              return cursor.var(
                  type_, 255,
                  arraysize=cursor.arraysize,
                  outconverter=outconverter
              )
  
          return handler
  
  
  class _OracleNUMBER(_OracleNumeric):
      is_number = True
  
  
  
  
  class _OracleDate(sqltypes.Date):
      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 _OracleChar(sqltypes.CHAR):
      def get_dbapi_type(self, dbapi):
          return dbapi.FIXED_CHAR
  
  
  class _OracleNVarChar(sqltypes.NVARCHAR):
      def get_dbapi_type(self, dbapi):
          return getattr(dbapi, 'UNICODE', dbapi.STRING)
  
  
  class _OracleText(sqltypes.Text):
      def get_dbapi_type(self, dbapi):
          return dbapi.CLOB
  
  
  class _OracleLong(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 _OracleUnicodeText(sqltypes.UnicodeText):
      def get_dbapi_type(self, dbapi):
          return dbapi.NCLOB
  
  
  class _OracleBinary(sqltypes.LargeBinary):
      def get_dbapi_type(self, dbapi):
          return dbapi.BLOB
  
      def bind_processor(self, dialect):
          return None
  
      def result_processor(self, dialect, coltype):
          if not dialect.auto_convert_lobs:
              return None
          else:
              return super(_OracleBinary, self).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
  
      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):
              quoted_name = '"%s"' % name
              self._quoted_bind_names[name] = quoted_name
              return OracleCompiler.bindparam_string(self, quoted_name, **kw)
          else:
              return OracleCompiler.bindparam_string(self, name, **kw)
  
  
  class OracleExecutionContext_cx_oracle(OracleExecutionContext):
      out_parameters = None
  
      def _setup_quoted_bind_names(self):
          quoted_bind_names = self.compiled._quoted_bind_names
          if quoted_bind_names:
              for param in self.parameters:
                  for fromname, toname in quoted_bind_names.items():
                      param[toname] = param[fromname]
                      del param[fromname]
  
      def _handle_out_parameters(self):
          # if a single execute, check for outparams
          if len(self.compiled_parameters) == 1:
              quoted_bind_names = self.compiled._quoted_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'):
                          self.out_parameters[name] = type_impl._cx_oracle_var(
                              self.dialect, self.cursor)
                      else:
                          dbtype = type_impl.get_dbapi_type(self.dialect.dbapi)
                          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)
                              )
                          self.out_parameters[name] = self.cursor.var(dbtype)
                      self.parameters[0][quoted_bind_names.get(name, name)] = \
                          self.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):
          if not getattr(self.compiled, "_oracle_cx_sql_compiler", False):
              return
  
          self.out_parameters = {}
  
          if self.compiled._quoted_bind_names:
              self._setup_quoted_bind_names()
  
          self.set_input_sizes(
              self.compiled._quoted_bind_names,
              include_types=self.dialect._include_setinputsizes
          )
  
          self._handle_out_parameters()
  
          self._generate_cursor_outputtype_handler()
  
      def create_cursor(self):
          c = self._dbapi_connection.cursor()
          if self.dialect.arraysize:
              c.arraysize = self.dialect.arraysize
  
          return c
  
      def get_result_proxy(self):
          if self.out_parameters and self.compiled.returning:
              returning_params = [
                  self.out_parameters["ret_%d" % i].getvalue()
                  for i in range(len(self.out_parameters))
              ]
              return ReturningResultProxy(self, returning_params)
  
          result = _result.ResultProxy(self)
  
          if self.out_parameters:
              if self.compiled_parameters is not None and \
                      len(self.compiled_parameters) == 1:
                  result.out_parameters = out_parameters = {}
  
                  for bind, name in self.compiled.bind_names.items():
                      if name in self.out_parameters:
                          type = bind.type
                          impl_type = type.dialect_impl(self.dialect)
                          dbapi_type = impl_type.get_dbapi_type(
                              self.dialect.dbapi)
                          result_processor = impl_type.\
                              result_processor(self.dialect,
                                               dbapi_type)
                          if result_processor is not None:
                              out_parameters[name] = \
                                  result_processor(
                                      self.out_parameters[name].getvalue())
                          else:
                              out_parameters[name] = self.out_parameters[
                                  name].getvalue()
              else:
                  result.out_parameters = dict(
                                              (k, v.getvalue())
                      for k, v in self.out_parameters.items()
                  )
  
          return result
  
  
  class ReturningResultProxy(_result.FullyBufferedResultProxy):
      """Result proxy which stuffs the _returning clause + outparams
      into the fetch."""
  
      def __init__(self, context, returning_params):
          self._returning_params = returning_params
          super(ReturningResultProxy, self).__init__(context)
  
      def _cursor_description(self):
          returning = self.context.compiled.returning
          return [
              (getattr(col, 'name', col.anon_label), None)
              for col in returning
          ]
  
      def _buffer_rows(self):
          return collections.deque(
              [tuple(self._returning_params)]
          )
  
  
  class OracleDialect_cx_oracle(OracleDialect):
      execution_ctx_cls = OracleExecutionContext_cx_oracle
      statement_compiler = OracleCompiler_cx_oracle
  
      supports_sane_rowcount = True
      supports_sane_multi_rowcount = True
  
      supports_unicode_statements = True
      supports_unicode_binds = True
  
      driver = "cx_oracle"
  
      colspecs = colspecs = {
          sqltypes.Numeric: _OracleNumeric,
          sqltypes.Float: _OracleNumeric,
          sqltypes.Integer: _OracleInteger,
          oracle.NUMBER: _OracleNUMBER,
  
          sqltypes.Date: _OracleDate,
          sqltypes.LargeBinary: _OracleBinary,
          sqltypes.Boolean: oracle._OracleBoolean,
          sqltypes.Interval: _OracleInterval,
          oracle.INTERVAL: _OracleInterval,
          sqltypes.Text: _OracleText,
          sqltypes.String: _OracleString,
          sqltypes.UnicodeText: _OracleUnicodeText,
          sqltypes.CHAR: _OracleChar,
          sqltypes.Enum: _OracleEnum,
  
          oracle.LONG: _OracleLong,
          oracle.RAW: _OracleRaw,
          sqltypes.Unicode: _OracleNVarChar,
          sqltypes.NVARCHAR: _OracleNVarChar,
          oracle.ROWID: _OracleRowid,
      }
  
      execute_sequence_format = list
  
      def __init__(self,
                   auto_convert_lobs=True,
                   threaded=True,
                   coerce_to_unicode=False,
                   coerce_to_decimal=True,
                   arraysize=50,
                   **kwargs):
  
          self._pop_deprecated_kwargs(kwargs)
  
          OracleDialect.__init__(self, **kwargs)
          self.threaded = threaded
          self.arraysize = arraysize
          self.auto_convert_lobs = auto_convert_lobs
          self.coerce_to_unicode = coerce_to_unicode
          self.coerce_to_decimal = coerce_to_decimal
  
          cx_Oracle = self.dbapi
  
          if cx_Oracle is None:
              self._include_setinputsizes = {}
              self.cx_oracle_ver = (0, 0, 0)
          else:
              self.cx_oracle_ver = self._parse_cx_oracle_ver(cx_Oracle.version)
              if self.cx_oracle_ver < (5, 0) and self.cx_oracle_ver > (0, 0, 0):
                  raise exc.InvalidRequestError(
                      "cx_Oracle version 5.0 and above are supported")
  
              self._has_native_int = hasattr(cx_Oracle, "NATIVE_INT")
  
              self._include_setinputsizes = {
                  cx_Oracle.NCLOB, cx_Oracle.CLOB, cx_Oracle.LOB,
                  cx_Oracle.BLOB, cx_Oracle.FIXED_CHAR,
              }
  
          self._is_cx_oracle_6 = self.cx_oracle_ver >= (6, )
  
      def _pop_deprecated_kwargs(self, kwargs):
          auto_setinputsizes = kwargs.pop('auto_setinputsizes', None)
          exclude_setinputsizes = kwargs.pop('exclude_setinputsizes', None)
          if auto_setinputsizes or exclude_setinputsizes:
              util.warn_deprecated(
                  "auto_setinputsizes and exclude_setinputsizes are deprecated. "
                  "Modern cx_Oracle only requires that LOB types are part "
                  "of this behavior, and these parameters no longer have any "
                  "effect.")
          allow_twophase = kwargs.pop('allow_twophase', None)
          if allow_twophase is not None:
              util.warn.deprecated(
                  "allow_twophase is deprecated.  The cx_Oracle dialect no "
                  "longer supports two-phase transaction mode."
              )
  
      def _parse_cx_oracle_ver(self, version):
          m = re.match(r'(\d+)\.(\d+)(?:\.(\d+))?', version)
          if m:
              return tuple(
                  int(x)
                  for x in m.group(1, 2, 3)
                  if x is not None)
          else:
              return (0, 0, 0)
  
      @classmethod
      def dbapi(cls):
          import cx_Oracle
          return cx_Oracle
  
      def initialize(self, connection):
          super(OracleDialect_cx_oracle, self).initialize(connection)
          if self._is_oracle_8:
              self.supports_unicode_binds = False
  
          self._detect_decimal_char(connection)
  
      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
  
          self._decimal_char = connection.scalar(
              "select value from nls_session_parameters "
              "where parameter = 'NLS_NUMERIC_CHARACTERS'")[0]
          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:
                  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
                      )
  
              # allow all strings to come back natively as Unicode
              elif dialect.coerce_to_unicode and \
                      default_type in (cx_Oracle.STRING, cx_Oracle.FIXED_CHAR):
                  return cursor.var(
                      util.text_type, size, cursor.arraysize
                  )
              elif dialect.auto_convert_lobs and default_type in (
                      cx_Oracle.CLOB, cx_Oracle.NCLOB, cx_Oracle.BLOB
              ):
                  return cursor.var(
                      default_type, size, cursor.arraysize,
                      outconverter=lambda value: value.read()
                  )
          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):
          dialect_opts = dict(url.query)
  
          for opt in ('use_ansi', 'auto_setinputsizes', 'auto_convert_lobs',
                      'threaded', 'allow_twophase'):
              if opt in dialect_opts:
                  util.coerce_kw_type(dialect_opts, opt, bool)
                  setattr(self, opt, dialect_opts[opt])
  
          database = url.database
          service_name = dialect_opts.get('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
  
          opts = dict(
              threaded=self.threaded,
          )
  
          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 'mode' in url.query:
              opts['mode'] = url.query['mode']
              if isinstance(opts['mode'], util.string_types):
                  mode = opts['mode'].upper()
                  if mode == 'SYSDBA':
                      opts['mode'] = self.dbapi.SYSDBA
                  elif mode == 'SYSOPER':
                      opts['mode'] = self.dbapi.SYSOPER
                  else:
                      util.coerce_kw_type(opts, 'mode', int)
          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)):
              return "not connected" in str(e)
          elif hasattr(error, 'code'):
              # 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 error.code in (28, 3114, 3113, 3135, 1033, 2396)
          else:
              return False
  
      def create_xid(self):
          """create a two-phase transaction ID.
  
          this id will be passed to do_begin_twophase(), do_rollback_twophase(),
          do_commit_twophase().  its format is unspecified.
  
          .. deprecated:: two-phase transaction support is no longer functional
             in SQLAlchemy's cx_Oracle dialect as of cx_Oracle 6.0b1
  
          """
  
          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)
  
      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)
  
      def do_commit_twophase(self, connection, xid, is_prepared=True,
                             recover=False):
          if not is_prepared:
              self.do_commit(connection.connection)
          else:
              oci_prepared = connection.info['cx_oracle_prepared']
              if oci_prepared:
                  self.do_commit(connection.connection)
  
      def do_recover_twophase(self, connection):
          connection.info.pop('cx_oracle_prepared', None)
  
  dialect = OracleDialect_cx_oracle
  