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bflw/venv/lib/python3.11/site-packages/sqlalchemy/engine/default.py

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# engine/default.py
# Copyright (C) 2005-2022 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
"""Default implementations of per-dialect sqlalchemy.engine classes.
These are semi-private implementation classes which are only of importance
to database dialect authors; dialects will usually use the classes here
as the base class for their own corresponding classes.
"""
import codecs
import functools
import random
import re
import weakref
from . import characteristics
from . import cursor as _cursor
from . import interfaces
from .base import Connection
from .. import event
from .. import exc
from .. import pool
from .. import processors
from .. import types as sqltypes
from .. import util
from ..sql import compiler
from ..sql import expression
from ..sql.elements import quoted_name
AUTOCOMMIT_REGEXP = re.compile(
r"\s*(?:UPDATE|INSERT|CREATE|DELETE|DROP|ALTER)", re.I | re.UNICODE
)
# When we're handed literal SQL, ensure it's a SELECT query
SERVER_SIDE_CURSOR_RE = re.compile(r"\s*SELECT", re.I | re.UNICODE)
CACHE_HIT = util.symbol("CACHE_HIT")
CACHE_MISS = util.symbol("CACHE_MISS")
CACHING_DISABLED = util.symbol("CACHING_DISABLED")
NO_CACHE_KEY = util.symbol("NO_CACHE_KEY")
NO_DIALECT_SUPPORT = util.symbol("NO_DIALECT_SUPPORT")
class DefaultDialect(interfaces.Dialect):
"""Default implementation of Dialect"""
statement_compiler = compiler.SQLCompiler
ddl_compiler = compiler.DDLCompiler
type_compiler = compiler.GenericTypeCompiler
preparer = compiler.IdentifierPreparer
supports_alter = True
supports_comments = False
inline_comments = False
use_setinputsizes = False
supports_statement_cache = True
# the first value we'd get for an autoincrement
# column.
default_sequence_base = 1
# most DBAPIs happy with this for execute().
# not cx_oracle.
execute_sequence_format = tuple
supports_schemas = True
supports_views = True
supports_sequences = False
sequences_optional = False
preexecute_autoincrement_sequences = False
supports_identity_columns = False
postfetch_lastrowid = True
implicit_returning = False
full_returning = False
insert_executemany_returning = False
cte_follows_insert = False
supports_native_enum = False
supports_native_boolean = False
non_native_boolean_check_constraint = True
supports_simple_order_by_label = True
tuple_in_values = False
connection_characteristics = util.immutabledict(
{"isolation_level": characteristics.IsolationLevelCharacteristic()}
)
engine_config_types = util.immutabledict(
[
("convert_unicode", util.bool_or_str("force")),
("pool_timeout", util.asint),
("echo", util.bool_or_str("debug")),
("echo_pool", util.bool_or_str("debug")),
("pool_recycle", util.asint),
("pool_size", util.asint),
("max_overflow", util.asint),
("future", util.asbool),
]
)
# if the NUMERIC type
# returns decimal.Decimal.
# *not* the FLOAT type however.
supports_native_decimal = False
if util.py3k:
supports_unicode_statements = True
supports_unicode_binds = True
returns_unicode_strings = sqltypes.String.RETURNS_UNICODE
description_encoding = None
else:
supports_unicode_statements = False
supports_unicode_binds = False
returns_unicode_strings = sqltypes.String.RETURNS_UNKNOWN
description_encoding = "use_encoding"
name = "default"
# length at which to truncate
# any identifier.
max_identifier_length = 9999
_user_defined_max_identifier_length = None
isolation_level = None
# sub-categories of max_identifier_length.
# currently these accommodate for MySQL which allows alias names
# of 255 but DDL names only of 64.
max_index_name_length = None
max_constraint_name_length = None
supports_sane_rowcount = True
supports_sane_multi_rowcount = True
colspecs = {}
default_paramstyle = "named"
supports_default_values = False
"""dialect supports INSERT... DEFAULT VALUES syntax"""
supports_default_metavalue = False
"""dialect supports INSERT... VALUES (DEFAULT) syntax"""
# not sure if this is a real thing but the compiler will deliver it
# if this is the only flag enabled.
supports_empty_insert = True
"""dialect supports INSERT () VALUES ()"""
supports_multivalues_insert = False
supports_is_distinct_from = True
supports_server_side_cursors = False
server_side_cursors = False
# extra record-level locking features (#4860)
supports_for_update_of = False
server_version_info = None
default_schema_name = None
construct_arguments = None
"""Optional set of argument specifiers for various SQLAlchemy
constructs, typically schema items.
To implement, establish as a series of tuples, as in::
construct_arguments = [
(schema.Index, {
"using": False,
"where": None,
"ops": None
})
]
If the above construct is established on the PostgreSQL dialect,
the :class:`.Index` construct will now accept the keyword arguments
``postgresql_using``, ``postgresql_where``, nad ``postgresql_ops``.
Any other argument specified to the constructor of :class:`.Index`
which is prefixed with ``postgresql_`` will raise :class:`.ArgumentError`.
A dialect which does not include a ``construct_arguments`` member will
not participate in the argument validation system. For such a dialect,
any argument name is accepted by all participating constructs, within
the namespace of arguments prefixed with that dialect name. The rationale
here is so that third-party dialects that haven't yet implemented this
feature continue to function in the old way.
.. versionadded:: 0.9.2
.. seealso::
:class:`.DialectKWArgs` - implementing base class which consumes
:attr:`.DefaultDialect.construct_arguments`
"""
# indicates symbol names are
# UPPERCASEd if they are case insensitive
# within the database.
# if this is True, the methods normalize_name()
# and denormalize_name() must be provided.
requires_name_normalize = False
reflection_options = ()
dbapi_exception_translation_map = util.immutabledict()
"""mapping used in the extremely unusual case that a DBAPI's
published exceptions don't actually have the __name__ that they
are linked towards.
.. versionadded:: 1.0.5
"""
is_async = False
CACHE_HIT = CACHE_HIT
CACHE_MISS = CACHE_MISS
CACHING_DISABLED = CACHING_DISABLED
NO_CACHE_KEY = NO_CACHE_KEY
NO_DIALECT_SUPPORT = NO_DIALECT_SUPPORT
has_terminate = False
@util.deprecated_params(
convert_unicode=(
"1.3",
"The :paramref:`_sa.create_engine.convert_unicode` parameter "
"and corresponding dialect-level parameters are deprecated, "
"and will be removed in a future release. Modern DBAPIs support "
"Python Unicode natively and this parameter is unnecessary.",
),
empty_in_strategy=(
"1.4",
"The :paramref:`_sa.create_engine.empty_in_strategy` keyword is "
"deprecated, and no longer has any effect. All IN expressions "
"are now rendered using "
'the "expanding parameter" strategy which renders a set of bound'
'expressions, or an "empty set" SELECT, at statement execution'
"time.",
),
case_sensitive=(
"1.4",
"The :paramref:`_sa.create_engine.case_sensitive` parameter "
"is deprecated and will be removed in a future release. "
"Applications should work with result column names in a case "
"sensitive fashion.",
),
server_side_cursors=(
"1.4",
"The :paramref:`_sa.create_engine.server_side_cursors` parameter "
"is deprecated and will be removed in a future release. Please "
"use the "
":paramref:`_engine.Connection.execution_options.stream_results` "
"parameter.",
),
)
def __init__(
self,
convert_unicode=False,
encoding="utf-8",
paramstyle=None,
dbapi=None,
implicit_returning=None,
case_sensitive=True,
supports_native_boolean=None,
max_identifier_length=None,
label_length=None,
# int() is because the @deprecated_params decorator cannot accommodate
# the direct reference to the "NO_LINTING" object
compiler_linting=int(compiler.NO_LINTING),
server_side_cursors=False,
**kwargs
):
if not getattr(self, "ported_sqla_06", True):
util.warn(
"The %s dialect is not yet ported to the 0.6 format"
% self.name
)
if server_side_cursors:
if not self.supports_server_side_cursors:
raise exc.ArgumentError(
"Dialect %s does not support server side cursors" % self
)
else:
self.server_side_cursors = True
self.convert_unicode = convert_unicode
self.encoding = encoding
self.positional = False
self._ischema = None
self.dbapi = dbapi
if paramstyle is not None:
self.paramstyle = paramstyle
elif self.dbapi is not None:
self.paramstyle = self.dbapi.paramstyle
else:
self.paramstyle = self.default_paramstyle
if implicit_returning is not None:
self.implicit_returning = implicit_returning
self.positional = self.paramstyle in ("qmark", "format", "numeric")
self.identifier_preparer = self.preparer(self)
self.type_compiler = self.type_compiler(self)
if supports_native_boolean is not None:
self.supports_native_boolean = supports_native_boolean
self.case_sensitive = case_sensitive
self._user_defined_max_identifier_length = max_identifier_length
if self._user_defined_max_identifier_length:
self.max_identifier_length = (
self._user_defined_max_identifier_length
)
self.label_length = label_length
self.compiler_linting = compiler_linting
if self.description_encoding == "use_encoding":
self._description_decoder = (
processors.to_unicode_processor_factory
)(encoding)
elif self.description_encoding is not None:
self._description_decoder = (
processors.to_unicode_processor_factory
)(self.description_encoding)
self._encoder = codecs.getencoder(self.encoding)
self._decoder = processors.to_unicode_processor_factory(self.encoding)
def _ensure_has_table_connection(self, arg):
if not isinstance(arg, Connection):
raise exc.ArgumentError(
"The argument passed to Dialect.has_table() should be a "
"%s, got %s. "
"Additionally, the Dialect.has_table() method is for "
"internal dialect "
"use only; please use "
"``inspect(some_engine).has_table(<tablename>>)`` "
"for public API use." % (Connection, type(arg))
)
@util.memoized_property
def _supports_statement_cache(self):
ssc = self.__class__.__dict__.get("supports_statement_cache", None)
if ssc is None:
util.warn(
"Dialect %s:%s will not make use of SQL compilation caching "
"as it does not set the 'supports_statement_cache' attribute "
"to ``True``. This can have "
"significant performance implications including some "
"performance degradations in comparison to prior SQLAlchemy "
"versions. Dialect maintainers should seek to set this "
"attribute to True after appropriate development and testing "
"for SQLAlchemy 1.4 caching support. Alternatively, this "
"attribute may be set to False which will disable this "
"warning." % (self.name, self.driver),
code="cprf",
)
return bool(ssc)
@util.memoized_property
def _type_memos(self):
return weakref.WeakKeyDictionary()
@property
def dialect_description(self):
return self.name + "+" + self.driver
@property
def supports_sane_rowcount_returning(self):
"""True if this dialect supports sane rowcount even if RETURNING is
in use.
For dialects that don't support RETURNING, this is synonymous with
``supports_sane_rowcount``.
"""
return self.supports_sane_rowcount
@classmethod
def get_pool_class(cls, url):
return getattr(cls, "poolclass", pool.QueuePool)
def get_dialect_pool_class(self, url):
return self.get_pool_class(url)
@classmethod
def load_provisioning(cls):
package = ".".join(cls.__module__.split(".")[0:-1])
try:
__import__(package + ".provision")
except ImportError:
pass
def initialize(self, connection):
try:
self.server_version_info = self._get_server_version_info(
connection
)
except NotImplementedError:
self.server_version_info = None
try:
self.default_schema_name = self._get_default_schema_name(
connection
)
except NotImplementedError:
self.default_schema_name = None
try:
self.default_isolation_level = self.get_default_isolation_level(
connection.connection
)
except NotImplementedError:
self.default_isolation_level = None
if self.returns_unicode_strings is sqltypes.String.RETURNS_UNKNOWN:
if util.py3k:
raise exc.InvalidRequestError(
"RETURNS_UNKNOWN is unsupported in Python 3"
)
self.returns_unicode_strings = self._check_unicode_returns(
connection
)
if (
self.description_encoding is not None
and self._check_unicode_description(connection)
):
self._description_decoder = self.description_encoding = None
if not self._user_defined_max_identifier_length:
max_ident_length = self._check_max_identifier_length(connection)
if max_ident_length:
self.max_identifier_length = max_ident_length
if (
self.label_length
and self.label_length > self.max_identifier_length
):
raise exc.ArgumentError(
"Label length of %d is greater than this dialect's"
" maximum identifier length of %d"
% (self.label_length, self.max_identifier_length)
)
def on_connect(self):
# inherits the docstring from interfaces.Dialect.on_connect
return None
def _check_max_identifier_length(self, connection):
"""Perform a connection / server version specific check to determine
the max_identifier_length.
If the dialect's class level max_identifier_length should be used,
can return None.
.. versionadded:: 1.3.9
"""
return None
def get_default_isolation_level(self, dbapi_conn):
"""Given a DBAPI connection, return its isolation level, or
a default isolation level if one cannot be retrieved.
May be overridden by subclasses in order to provide a
"fallback" isolation level for databases that cannot reliably
retrieve the actual isolation level.
By default, calls the :meth:`_engine.Interfaces.get_isolation_level`
method, propagating any exceptions raised.
.. versionadded:: 1.3.22
"""
return self.get_isolation_level(dbapi_conn)
def _check_unicode_returns(self, connection, additional_tests=None):
# this now runs in py2k only and will be removed in 2.0; disabled for
# Python 3 in all cases under #5315
if util.py2k and not self.supports_unicode_statements:
cast_to = util.binary_type
else:
cast_to = util.text_type
if self.positional:
parameters = self.execute_sequence_format()
else:
parameters = {}
def check_unicode(test):
statement = cast_to(expression.select(test).compile(dialect=self))
try:
cursor = connection.connection.cursor()
connection._cursor_execute(cursor, statement, parameters)
row = cursor.fetchone()
cursor.close()
except exc.DBAPIError as de:
# note that _cursor_execute() will have closed the cursor
# if an exception is thrown.
util.warn(
"Exception attempting to "
"detect unicode returns: %r" % de
)
return False
else:
return isinstance(row[0], util.text_type)
tests = [
# detect plain VARCHAR
expression.cast(
expression.literal_column("'test plain returns'"),
sqltypes.VARCHAR(60),
),
# detect if there's an NVARCHAR type with different behavior
# available
expression.cast(
expression.literal_column("'test unicode returns'"),
sqltypes.Unicode(60),
),
]
if additional_tests:
tests += additional_tests
results = {check_unicode(test) for test in tests}
if results.issuperset([True, False]):
return sqltypes.String.RETURNS_CONDITIONAL
else:
return (
sqltypes.String.RETURNS_UNICODE
if results == {True}
else sqltypes.String.RETURNS_BYTES
)
def _check_unicode_description(self, connection):
# all DBAPIs on Py2K return cursor.description as encoded
if util.py2k and not self.supports_unicode_statements:
cast_to = util.binary_type
else:
cast_to = util.text_type
cursor = connection.connection.cursor()
try:
cursor.execute(
cast_to(
expression.select(
expression.literal_column("'x'").label("some_label")
).compile(dialect=self)
)
)
return isinstance(cursor.description[0][0], util.text_type)
finally:
cursor.close()
def type_descriptor(self, typeobj):
"""Provide a database-specific :class:`.TypeEngine` object, given
the generic object which comes from the types module.
This method looks for a dictionary called
``colspecs`` as a class or instance-level variable,
and passes on to :func:`_types.adapt_type`.
"""
return sqltypes.adapt_type(typeobj, self.colspecs)
def has_index(self, connection, table_name, index_name, schema=None):
if not self.has_table(connection, table_name, schema=schema):
return False
for idx in self.get_indexes(connection, table_name, schema=schema):
if idx["name"] == index_name:
return True
else:
return False
def validate_identifier(self, ident):
if len(ident) > self.max_identifier_length:
raise exc.IdentifierError(
"Identifier '%s' exceeds maximum length of %d characters"
% (ident, self.max_identifier_length)
)
def connect(self, *cargs, **cparams):
# inherits the docstring from interfaces.Dialect.connect
return self.dbapi.connect(*cargs, **cparams)
def create_connect_args(self, url):
# inherits the docstring from interfaces.Dialect.create_connect_args
opts = url.translate_connect_args()
opts.update(url.query)
return [[], opts]
def set_engine_execution_options(self, engine, opts):
supported_names = set(self.connection_characteristics).intersection(
opts
)
if supported_names:
characteristics = util.immutabledict(
(name, opts[name]) for name in supported_names
)
@event.listens_for(engine, "engine_connect")
def set_connection_characteristics(connection, branch):
if not branch:
self._set_connection_characteristics(
connection, characteristics
)
def set_connection_execution_options(self, connection, opts):
supported_names = set(self.connection_characteristics).intersection(
opts
)
if supported_names:
characteristics = util.immutabledict(
(name, opts[name]) for name in supported_names
)
self._set_connection_characteristics(connection, characteristics)
def _set_connection_characteristics(self, connection, characteristics):
characteristic_values = [
(name, self.connection_characteristics[name], value)
for name, value in characteristics.items()
]
if connection.in_transaction():
trans_objs = [
(name, obj)
for name, obj, value in characteristic_values
if obj.transactional
]
if trans_objs:
if connection._is_future:
raise exc.InvalidRequestError(
"This connection has already initialized a SQLAlchemy "
"Transaction() object via begin() or autobegin; "
"%s may not be altered unless rollback() or commit() "
"is called first."
% (", ".join(name for name, obj in trans_objs))
)
else:
util.warn(
"Connection is already established with a "
"Transaction; "
"setting %s may implicitly rollback or "
"commit "
"the existing transaction, or have no effect until "
"next transaction"
% (", ".join(name for name, obj in trans_objs))
)
dbapi_connection = connection.connection.dbapi_connection
for name, characteristic, value in characteristic_values:
characteristic.set_characteristic(self, dbapi_connection, value)
connection.connection._connection_record.finalize_callback.append(
functools.partial(self._reset_characteristics, characteristics)
)
def _reset_characteristics(self, characteristics, dbapi_connection):
for characteristic_name in characteristics:
characteristic = self.connection_characteristics[
characteristic_name
]
characteristic.reset_characteristic(self, dbapi_connection)
def do_begin(self, dbapi_connection):
pass
def do_rollback(self, dbapi_connection):
dbapi_connection.rollback()
def do_commit(self, dbapi_connection):
dbapi_connection.commit()
def do_terminate(self, dbapi_connection):
self.do_close(dbapi_connection)
def do_close(self, dbapi_connection):
dbapi_connection.close()
@util.memoized_property
def _dialect_specific_select_one(self):
return str(expression.select(1).compile(dialect=self))
def do_ping(self, dbapi_connection):
cursor = None
try:
cursor = dbapi_connection.cursor()
try:
cursor.execute(self._dialect_specific_select_one)
finally:
cursor.close()
except self.dbapi.Error as err:
if self.is_disconnect(err, dbapi_connection, cursor):
return False
else:
raise
else:
return True
def create_xid(self):
"""Create a random two-phase transaction ID.
This id will be passed to do_begin_twophase(), do_rollback_twophase(),
do_commit_twophase(). Its format is unspecified.
"""
return "_sa_%032x" % random.randint(0, 2 ** 128)
def do_savepoint(self, connection, name):
connection.execute(expression.SavepointClause(name))
def do_rollback_to_savepoint(self, connection, name):
connection.execute(expression.RollbackToSavepointClause(name))
def do_release_savepoint(self, connection, name):
connection.execute(expression.ReleaseSavepointClause(name))
def do_executemany(self, cursor, statement, parameters, context=None):
cursor.executemany(statement, parameters)
def do_execute(self, cursor, statement, parameters, context=None):
cursor.execute(statement, parameters)
def do_execute_no_params(self, cursor, statement, context=None):
cursor.execute(statement)
def is_disconnect(self, e, connection, cursor):
return False
def reset_isolation_level(self, dbapi_conn):
# default_isolation_level is read from the first connection
# after the initial set of 'isolation_level', if any, so is
# the configured default of this dialect.
self.set_isolation_level(dbapi_conn, self.default_isolation_level)
def normalize_name(self, name):
if name is None:
return None
if util.py2k:
if isinstance(name, str):
name = name.decode(self.encoding)
name_lower = name.lower()
name_upper = name.upper()
if name_upper == name_lower:
# name has no upper/lower conversion, e.g. non-european characters.
# return unchanged
return name
elif name_upper == name and not (
self.identifier_preparer._requires_quotes
)(name_lower):
# name is all uppercase and doesn't require quoting; normalize
# to all lower case
return name_lower
elif name_lower == name:
# name is all lower case, which if denormalized means we need to
# force quoting on it
return quoted_name(name, quote=True)
else:
# name is mixed case, means it will be quoted in SQL when used
# later, no normalizes
return name
def denormalize_name(self, name):
if name is None:
return None
name_lower = name.lower()
name_upper = name.upper()
if name_upper == name_lower:
# name has no upper/lower conversion, e.g. non-european characters.
# return unchanged
return name
elif name_lower == name and not (
self.identifier_preparer._requires_quotes
)(name_lower):
name = name_upper
if util.py2k:
if not self.supports_unicode_binds:
name = name.encode(self.encoding)
else:
name = unicode(name) # noqa
return name
def get_driver_connection(self, connection):
return connection
class _RendersLiteral(object):
def literal_processor(self, dialect):
def process(value):
return "'%s'" % value
return process
class _StrDateTime(_RendersLiteral, sqltypes.DateTime):
pass
class _StrDate(_RendersLiteral, sqltypes.Date):
pass
class _StrTime(_RendersLiteral, sqltypes.Time):
pass
class StrCompileDialect(DefaultDialect):
statement_compiler = compiler.StrSQLCompiler
ddl_compiler = compiler.DDLCompiler
type_compiler = compiler.StrSQLTypeCompiler
preparer = compiler.IdentifierPreparer
supports_statement_cache = True
supports_identity_columns = True
supports_sequences = True
sequences_optional = True
preexecute_autoincrement_sequences = False
implicit_returning = False
supports_native_boolean = True
supports_multivalues_insert = True
supports_simple_order_by_label = True
colspecs = {
sqltypes.DateTime: _StrDateTime,
sqltypes.Date: _StrDate,
sqltypes.Time: _StrTime,
}
class DefaultExecutionContext(interfaces.ExecutionContext):
isinsert = False
isupdate = False
isdelete = False
is_crud = False
is_text = False
isddl = False
executemany = False
compiled = None
statement = None
result_column_struct = None
returned_default_rows = None
execution_options = util.immutabledict()
include_set_input_sizes = None
exclude_set_input_sizes = None
cursor_fetch_strategy = _cursor._DEFAULT_FETCH
cache_stats = None
invoked_statement = None
_is_implicit_returning = False
_is_explicit_returning = False
_is_future_result = False
_is_server_side = False
_soft_closed = False
# a hook for SQLite's translation of
# result column names
# NOTE: pyhive is using this hook, can't remove it :(
_translate_colname = None
_expanded_parameters = util.immutabledict()
cache_hit = NO_CACHE_KEY
@classmethod
def _init_ddl(
cls,
dialect,
connection,
dbapi_connection,
execution_options,
compiled_ddl,
):
"""Initialize execution context for a DDLElement construct."""
self = cls.__new__(cls)
self.root_connection = connection
self._dbapi_connection = dbapi_connection
self.dialect = connection.dialect
self.compiled = compiled = compiled_ddl
self.isddl = True
self.execution_options = execution_options
self._is_future_result = (
connection._is_future
or self.execution_options.get("future_result", False)
)
self.unicode_statement = util.text_type(compiled)
if compiled.schema_translate_map:
schema_translate_map = self.execution_options.get(
"schema_translate_map", {}
)
rst = compiled.preparer._render_schema_translates
self.unicode_statement = rst(
self.unicode_statement, schema_translate_map
)
if not dialect.supports_unicode_statements:
self.statement = dialect._encoder(self.unicode_statement)[0]
else:
self.statement = self.unicode_statement
self.cursor = self.create_cursor()
self.compiled_parameters = []
if dialect.positional:
self.parameters = [dialect.execute_sequence_format()]
else:
self.parameters = [{}]
return self
@classmethod
def _init_compiled(
cls,
dialect,
connection,
dbapi_connection,
execution_options,
compiled,
parameters,
invoked_statement,
extracted_parameters,
cache_hit=CACHING_DISABLED,
):
"""Initialize execution context for a Compiled construct."""
self = cls.__new__(cls)
self.root_connection = connection
self._dbapi_connection = dbapi_connection
self.dialect = connection.dialect
self.extracted_parameters = extracted_parameters
self.invoked_statement = invoked_statement
self.compiled = compiled
self.cache_hit = cache_hit
self.execution_options = execution_options
self._is_future_result = (
connection._is_future
or self.execution_options.get("future_result", False)
)
self.result_column_struct = (
compiled._result_columns,
compiled._ordered_columns,
compiled._textual_ordered_columns,
compiled._ad_hoc_textual,
compiled._loose_column_name_matching,
)
self.isinsert = compiled.isinsert
self.isupdate = compiled.isupdate
self.isdelete = compiled.isdelete
self.is_text = compiled.isplaintext
if self.isinsert or self.isupdate or self.isdelete:
self.is_crud = True
self._is_explicit_returning = bool(compiled.statement._returning)
self._is_implicit_returning = bool(
compiled.returning and not compiled.statement._returning
)
if not parameters:
self.compiled_parameters = [
compiled.construct_params(
extracted_parameters=extracted_parameters,
escape_names=False,
)
]
else:
self.compiled_parameters = [
compiled.construct_params(
m,
escape_names=False,
_group_number=grp,
extracted_parameters=extracted_parameters,
)
for grp, m in enumerate(parameters)
]
self.executemany = len(parameters) > 1
# this must occur before create_cursor() since the statement
# has to be regexed in some cases for server side cursor
if util.py2k:
self.unicode_statement = util.text_type(compiled.string)
else:
self.unicode_statement = compiled.string
self.cursor = self.create_cursor()
if self.compiled.insert_prefetch or self.compiled.update_prefetch:
if self.executemany:
self._process_executemany_defaults()
else:
self._process_executesingle_defaults()
processors = compiled._bind_processors
if compiled.literal_execute_params or compiled.post_compile_params:
if self.executemany:
raise exc.InvalidRequestError(
"'literal_execute' or 'expanding' parameters can't be "
"used with executemany()"
)
expanded_state = compiled._process_parameters_for_postcompile(
self.compiled_parameters[0]
)
# re-assign self.unicode_statement
self.unicode_statement = expanded_state.statement
# used by set_input_sizes() which is needed for Oracle
self._expanded_parameters = expanded_state.parameter_expansion
processors = dict(processors)
processors.update(expanded_state.processors)
positiontup = expanded_state.positiontup
elif compiled.positional:
positiontup = self.compiled.positiontup
if compiled.schema_translate_map:
schema_translate_map = self.execution_options.get(
"schema_translate_map", {}
)
rst = compiled.preparer._render_schema_translates
self.unicode_statement = rst(
self.unicode_statement, schema_translate_map
)
# final self.unicode_statement is now assigned, encode if needed
# by dialect
if not dialect.supports_unicode_statements:
self.statement = self.unicode_statement.encode(
self.dialect.encoding
)
else:
self.statement = self.unicode_statement
# Convert the dictionary of bind parameter values
# into a dict or list to be sent to the DBAPI's
# execute() or executemany() method.
parameters = []
if compiled.positional:
for compiled_params in self.compiled_parameters:
param = [
processors[key](compiled_params[key])
if key in processors
else compiled_params[key]
for key in positiontup
]
parameters.append(dialect.execute_sequence_format(param))
else:
encode = not dialect.supports_unicode_statements
if encode:
encoder = dialect._encoder
for compiled_params in self.compiled_parameters:
escaped_bind_names = compiled.escaped_bind_names
if encode:
if escaped_bind_names:
param = {
encoder(escaped_bind_names.get(key, key))[
0
]: processors[key](compiled_params[key])
if key in processors
else compiled_params[key]
for key in compiled_params
}
else:
param = {
encoder(key)[0]: processors[key](
compiled_params[key]
)
if key in processors
else compiled_params[key]
for key in compiled_params
}
else:
if escaped_bind_names:
param = {
escaped_bind_names.get(key, key): processors[key](
compiled_params[key]
)
if key in processors
else compiled_params[key]
for key in compiled_params
}
else:
param = {
key: processors[key](compiled_params[key])
if key in processors
else compiled_params[key]
for key in compiled_params
}
parameters.append(param)
self.parameters = dialect.execute_sequence_format(parameters)
return self
@classmethod
def _init_statement(
cls,
dialect,
connection,
dbapi_connection,
execution_options,
statement,
parameters,
):
"""Initialize execution context for a string SQL statement."""
self = cls.__new__(cls)
self.root_connection = connection
self._dbapi_connection = dbapi_connection
self.dialect = connection.dialect
self.is_text = True
self.execution_options = execution_options
self._is_future_result = (
connection._is_future
or self.execution_options.get("future_result", False)
)
if not parameters:
if self.dialect.positional:
self.parameters = [dialect.execute_sequence_format()]
else:
self.parameters = [{}]
elif isinstance(parameters[0], dialect.execute_sequence_format):
self.parameters = parameters
elif isinstance(parameters[0], dict):
if dialect.supports_unicode_statements:
self.parameters = parameters
else:
self.parameters = [
{dialect._encoder(k)[0]: d[k] for k in d}
for d in parameters
] or [{}]
else:
self.parameters = [
dialect.execute_sequence_format(p) for p in parameters
]
self.executemany = len(parameters) > 1
if not dialect.supports_unicode_statements and isinstance(
statement, util.text_type
):
self.unicode_statement = statement
self.statement = dialect._encoder(statement)[0]
else:
self.statement = self.unicode_statement = statement
self.cursor = self.create_cursor()
return self
@classmethod
def _init_default(
cls, dialect, connection, dbapi_connection, execution_options
):
"""Initialize execution context for a ColumnDefault construct."""
self = cls.__new__(cls)
self.root_connection = connection
self._dbapi_connection = dbapi_connection
self.dialect = connection.dialect
self.execution_options = execution_options
self._is_future_result = (
connection._is_future
or self.execution_options.get("future_result", False)
)
self.cursor = self.create_cursor()
return self
def _get_cache_stats(self):
if self.compiled is None:
return "raw sql"
now = util.perf_counter()
ch = self.cache_hit
if ch is NO_CACHE_KEY:
return "no key %.5fs" % (now - self.compiled._gen_time,)
elif ch is CACHE_HIT:
return "cached since %.4gs ago" % (now - self.compiled._gen_time,)
elif ch is CACHE_MISS:
return "generated in %.5fs" % (now - self.compiled._gen_time,)
elif ch is CACHING_DISABLED:
return "caching disabled %.5fs" % (now - self.compiled._gen_time,)
elif ch is NO_DIALECT_SUPPORT:
return "dialect %s+%s does not support caching %.5fs" % (
self.dialect.name,
self.dialect.driver,
now - self.compiled._gen_time,
)
else:
return "unknown"
@util.memoized_property
def identifier_preparer(self):
if self.compiled:
return self.compiled.preparer
elif "schema_translate_map" in self.execution_options:
return self.dialect.identifier_preparer._with_schema_translate(
self.execution_options["schema_translate_map"]
)
else:
return self.dialect.identifier_preparer
@util.memoized_property
def engine(self):
return self.root_connection.engine
@util.memoized_property
def postfetch_cols(self):
return self.compiled.postfetch
@util.memoized_property
def prefetch_cols(self):
if self.isinsert:
return self.compiled.insert_prefetch
elif self.isupdate:
return self.compiled.update_prefetch
else:
return ()
@util.memoized_property
def returning_cols(self):
self.compiled.returning
@util.memoized_property
def no_parameters(self):
return self.execution_options.get("no_parameters", False)
@util.memoized_property
def should_autocommit(self):
autocommit = self.execution_options.get(
"autocommit",
not self.compiled
and self.statement
and expression.PARSE_AUTOCOMMIT
or False,
)
if autocommit is expression.PARSE_AUTOCOMMIT:
return self.should_autocommit_text(self.unicode_statement)
else:
return autocommit
def _execute_scalar(self, stmt, type_, parameters=None):
"""Execute a string statement on the current cursor, returning a
scalar result.
Used to fire off sequences, default phrases, and "select lastrowid"
types of statements individually or in the context of a parent INSERT
or UPDATE statement.
"""
conn = self.root_connection
if (
isinstance(stmt, util.text_type)
and not self.dialect.supports_unicode_statements
):
stmt = self.dialect._encoder(stmt)[0]
if "schema_translate_map" in self.execution_options:
schema_translate_map = self.execution_options.get(
"schema_translate_map", {}
)
rst = self.identifier_preparer._render_schema_translates
stmt = rst(stmt, schema_translate_map)
if not parameters:
if self.dialect.positional:
parameters = self.dialect.execute_sequence_format()
else:
parameters = {}
conn._cursor_execute(self.cursor, stmt, parameters, context=self)
r = self.cursor.fetchone()[0]
if type_ is not None:
# apply type post processors to the result
proc = type_._cached_result_processor(
self.dialect, self.cursor.description[0][1]
)
if proc:
return proc(r)
return r
@property
def connection(self):
conn = self.root_connection
if conn._is_future:
return conn
else:
return conn._branch()
def should_autocommit_text(self, statement):
return AUTOCOMMIT_REGEXP.match(statement)
def _use_server_side_cursor(self):
if not self.dialect.supports_server_side_cursors:
return False
if self.dialect.server_side_cursors:
# this is deprecated
use_server_side = self.execution_options.get(
"stream_results", True
) and (
(
self.compiled
and isinstance(
self.compiled.statement, expression.Selectable
)
or (
(
not self.compiled
or isinstance(
self.compiled.statement, expression.TextClause
)
)
and self.unicode_statement
and SERVER_SIDE_CURSOR_RE.match(self.unicode_statement)
)
)
)
else:
use_server_side = self.execution_options.get(
"stream_results", False
)
return use_server_side
def create_cursor(self):
if (
# inlining initial preference checks for SS cursors
self.dialect.supports_server_side_cursors
and (
self.execution_options.get("stream_results", False)
or (
self.dialect.server_side_cursors
and self._use_server_side_cursor()
)
)
):
self._is_server_side = True
return self.create_server_side_cursor()
else:
self._is_server_side = False
return self.create_default_cursor()
def create_default_cursor(self):
return self._dbapi_connection.cursor()
def create_server_side_cursor(self):
raise NotImplementedError()
def pre_exec(self):
pass
def get_out_parameter_values(self, names):
raise NotImplementedError(
"This dialect does not support OUT parameters"
)
def post_exec(self):
pass
def get_result_processor(self, type_, colname, coltype):
"""Return a 'result processor' for a given type as present in
cursor.description.
This has a default implementation that dialects can override
for context-sensitive result type handling.
"""
return type_._cached_result_processor(self.dialect, coltype)
def get_lastrowid(self):
"""return self.cursor.lastrowid, or equivalent, after an INSERT.
This may involve calling special cursor functions, issuing a new SELECT
on the cursor (or a new one), or returning a stored value that was
calculated within post_exec().
This function will only be called for dialects which support "implicit"
primary key generation, keep preexecute_autoincrement_sequences set to
False, and when no explicit id value was bound to the statement.
The function is called once for an INSERT statement that would need to
return the last inserted primary key for those dialects that make use
of the lastrowid concept. In these cases, it is called directly after
:meth:`.ExecutionContext.post_exec`.
"""
return self.cursor.lastrowid
def handle_dbapi_exception(self, e):
pass
@property
def rowcount(self):
return self.cursor.rowcount
def supports_sane_rowcount(self):
return self.dialect.supports_sane_rowcount
def supports_sane_multi_rowcount(self):
return self.dialect.supports_sane_multi_rowcount
def _setup_result_proxy(self):
exec_opt = self.execution_options
if self.is_crud or self.is_text:
result = self._setup_dml_or_text_result()
yp = sr = False
else:
yp = exec_opt.get("yield_per", None)
sr = self._is_server_side or exec_opt.get("stream_results", False)
strategy = self.cursor_fetch_strategy
if sr and strategy is _cursor._DEFAULT_FETCH:
strategy = _cursor.BufferedRowCursorFetchStrategy(
self.cursor, self.execution_options
)
cursor_description = (
strategy.alternate_cursor_description
or self.cursor.description
)
if cursor_description is None:
strategy = _cursor._NO_CURSOR_DQL
if self._is_future_result:
if self.root_connection.should_close_with_result:
raise exc.InvalidRequestError(
"can't use future_result=True with close_with_result"
)
result = _cursor.CursorResult(
self, strategy, cursor_description
)
else:
result = _cursor.LegacyCursorResult(
self, strategy, cursor_description
)
if (
self.compiled
and not self.isddl
and self.compiled.has_out_parameters
):
self._setup_out_parameters(result)
self._soft_closed = result._soft_closed
if yp:
result = result.yield_per(yp)
return result
def _setup_out_parameters(self, result):
out_bindparams = [
(param, name)
for param, name in self.compiled.bind_names.items()
if param.isoutparam
]
out_parameters = {}
for bindparam, raw_value in zip(
[param for param, name in out_bindparams],
self.get_out_parameter_values(
[name for param, name in out_bindparams]
),
):
type_ = bindparam.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:
raw_value = result_processor(raw_value)
out_parameters[bindparam.key] = raw_value
result.out_parameters = out_parameters
def _setup_dml_or_text_result(self):
if self.isinsert:
if self.compiled.postfetch_lastrowid:
self.inserted_primary_key_rows = (
self._setup_ins_pk_from_lastrowid()
)
# else if not self._is_implicit_returning,
# the default inserted_primary_key_rows accessor will
# return an "empty" primary key collection when accessed.
strategy = self.cursor_fetch_strategy
if self._is_server_side and strategy is _cursor._DEFAULT_FETCH:
strategy = _cursor.BufferedRowCursorFetchStrategy(
self.cursor, self.execution_options
)
cursor_description = (
strategy.alternate_cursor_description or self.cursor.description
)
if cursor_description is None:
strategy = _cursor._NO_CURSOR_DML
if self._is_future_result:
result = _cursor.CursorResult(self, strategy, cursor_description)
else:
result = _cursor.LegacyCursorResult(
self, strategy, cursor_description
)
if self.isinsert:
if self._is_implicit_returning:
rows = result.all()
self.returned_default_rows = rows
self.inserted_primary_key_rows = (
self._setup_ins_pk_from_implicit_returning(result, rows)
)
# test that it has a cursor metadata that is accurate. the
# first row will have been fetched and current assumptions
# are that the result has only one row, until executemany()
# support is added here.
assert result._metadata.returns_rows
result._soft_close()
elif not self._is_explicit_returning:
result._soft_close()
# we assume here the result does not return any rows.
# *usually*, this will be true. However, some dialects
# such as that of MSSQL/pyodbc need to SELECT a post fetch
# function so this is not necessarily true.
# assert not result.returns_rows
elif self.isupdate and self._is_implicit_returning:
row = result.fetchone()
self.returned_default_rows = [row]
result._soft_close()
# test that it has a cursor metadata that is accurate.
# the rows have all been fetched however.
assert result._metadata.returns_rows
elif not result._metadata.returns_rows:
# no results, get rowcount
# (which requires open cursor on some drivers
# such as kintersbasdb, mxodbc)
result.rowcount
result._soft_close()
return result
@util.memoized_property
def inserted_primary_key_rows(self):
# if no specific "get primary key" strategy was set up
# during execution, return a "default" primary key based
# on what's in the compiled_parameters and nothing else.
return self._setup_ins_pk_from_empty()
def _setup_ins_pk_from_lastrowid(self):
getter = self.compiled._inserted_primary_key_from_lastrowid_getter
lastrowid = self.get_lastrowid()
return [getter(lastrowid, self.compiled_parameters[0])]
def _setup_ins_pk_from_empty(self):
getter = self.compiled._inserted_primary_key_from_lastrowid_getter
return [getter(None, param) for param in self.compiled_parameters]
def _setup_ins_pk_from_implicit_returning(self, result, rows):
if not rows:
return []
getter = self.compiled._inserted_primary_key_from_returning_getter
compiled_params = self.compiled_parameters
return [
getter(row, param) for row, param in zip(rows, compiled_params)
]
def lastrow_has_defaults(self):
return (self.isinsert or self.isupdate) and bool(
self.compiled.postfetch
)
def _set_input_sizes(self):
"""Given a cursor and ClauseParameters, call the appropriate
style of ``setinputsizes()`` on the cursor, using DB-API types
from the bind parameter's ``TypeEngine`` objects.
This method only called by those dialects which require it,
currently cx_oracle, asyncpg and pg8000.
"""
if self.isddl or self.is_text:
return
inputsizes = self.compiled._get_set_input_sizes_lookup(
include_types=self.include_set_input_sizes,
exclude_types=self.exclude_set_input_sizes,
)
if inputsizes is None:
return
if self.dialect._has_events:
inputsizes = dict(inputsizes)
self.dialect.dispatch.do_setinputsizes(
inputsizes, self.cursor, self.statement, self.parameters, self
)
has_escaped_names = bool(self.compiled.escaped_bind_names)
if has_escaped_names:
escaped_bind_names = self.compiled.escaped_bind_names
if self.dialect.positional:
items = [
(key, self.compiled.binds[key])
for key in self.compiled.positiontup
]
else:
items = [
(key, bindparam)
for bindparam, key in self.compiled.bind_names.items()
]
generic_inputsizes = []
for key, bindparam in items:
if bindparam in self.compiled.literal_execute_params:
continue
if key in self._expanded_parameters:
if bindparam.type._is_tuple_type:
num = len(bindparam.type.types)
dbtypes = inputsizes[bindparam]
generic_inputsizes.extend(
(
(
escaped_bind_names.get(paramname, paramname)
if has_escaped_names
else paramname
),
dbtypes[idx % num],
bindparam.type.types[idx % num],
)
for idx, paramname in enumerate(
self._expanded_parameters[key]
)
)
else:
dbtype = inputsizes.get(bindparam, None)
generic_inputsizes.extend(
(
(
escaped_bind_names.get(paramname, paramname)
if has_escaped_names
else paramname
),
dbtype,
bindparam.type,
)
for paramname in self._expanded_parameters[key]
)
else:
dbtype = inputsizes.get(bindparam, None)
escaped_name = (
escaped_bind_names.get(key, key)
if has_escaped_names
else key
)
generic_inputsizes.append(
(escaped_name, dbtype, bindparam.type)
)
try:
self.dialect.do_set_input_sizes(
self.cursor, generic_inputsizes, self
)
except BaseException as e:
self.root_connection._handle_dbapi_exception(
e, None, None, None, self
)
def _exec_default(self, column, default, type_):
if default.is_sequence:
return self.fire_sequence(default, type_)
elif default.is_callable:
self.current_column = column
return default.arg(self)
elif default.is_clause_element:
return self._exec_default_clause_element(column, default, type_)
else:
return default.arg
def _exec_default_clause_element(self, column, default, type_):
# execute a default that's a complete clause element. Here, we have
# to re-implement a miniature version of the compile->parameters->
# cursor.execute() sequence, since we don't want to modify the state
# of the connection / result in progress or create new connection/
# result objects etc.
# .. versionchanged:: 1.4
if not default._arg_is_typed:
default_arg = expression.type_coerce(default.arg, type_)
else:
default_arg = default.arg
compiled = expression.select(default_arg).compile(dialect=self.dialect)
compiled_params = compiled.construct_params()
processors = compiled._bind_processors
if compiled.positional:
positiontup = compiled.positiontup
parameters = self.dialect.execute_sequence_format(
[
processors[key](compiled_params[key])
if key in processors
else compiled_params[key]
for key in positiontup
]
)
else:
parameters = dict(
(
key,
processors[key](compiled_params[key])
if key in processors
else compiled_params[key],
)
for key in compiled_params
)
return self._execute_scalar(
util.text_type(compiled), type_, parameters=parameters
)
current_parameters = None
"""A dictionary of parameters applied to the current row.
This attribute is only available in the context of a user-defined default
generation function, e.g. as described at :ref:`context_default_functions`.
It consists of a dictionary which includes entries for each column/value
pair that is to be part of the INSERT or UPDATE statement. The keys of the
dictionary will be the key value of each :class:`_schema.Column`,
which is usually
synonymous with the name.
Note that the :attr:`.DefaultExecutionContext.current_parameters` attribute
does not accommodate for the "multi-values" feature of the
:meth:`_expression.Insert.values` method. The
:meth:`.DefaultExecutionContext.get_current_parameters` method should be
preferred.
.. seealso::
:meth:`.DefaultExecutionContext.get_current_parameters`
:ref:`context_default_functions`
"""
def get_current_parameters(self, isolate_multiinsert_groups=True):
"""Return a dictionary of parameters applied to the current row.
This method can only be used in the context of a user-defined default
generation function, e.g. as described at
:ref:`context_default_functions`. When invoked, a dictionary is
returned which includes entries for each column/value pair that is part
of the INSERT or UPDATE statement. The keys of the dictionary will be
the key value of each :class:`_schema.Column`,
which is usually synonymous
with the name.
:param isolate_multiinsert_groups=True: indicates that multi-valued
INSERT constructs created using :meth:`_expression.Insert.values`
should be
handled by returning only the subset of parameters that are local
to the current column default invocation. When ``False``, the
raw parameters of the statement are returned including the
naming convention used in the case of multi-valued INSERT.
.. versionadded:: 1.2 added
:meth:`.DefaultExecutionContext.get_current_parameters`
which provides more functionality over the existing
:attr:`.DefaultExecutionContext.current_parameters`
attribute.
.. seealso::
:attr:`.DefaultExecutionContext.current_parameters`
:ref:`context_default_functions`
"""
try:
parameters = self.current_parameters
column = self.current_column
except AttributeError:
raise exc.InvalidRequestError(
"get_current_parameters() can only be invoked in the "
"context of a Python side column default function"
)
compile_state = self.compiled.compile_state
if (
isolate_multiinsert_groups
and self.isinsert
and compile_state._has_multi_parameters
):
if column._is_multiparam_column:
index = column.index + 1
d = {column.original.key: parameters[column.key]}
else:
d = {column.key: parameters[column.key]}
index = 0
keys = compile_state._dict_parameters.keys()
d.update(
(key, parameters["%s_m%d" % (key, index)]) for key in keys
)
return d
else:
return parameters
def get_insert_default(self, column):
if column.default is None:
return None
else:
return self._exec_default(column, column.default, column.type)
def get_update_default(self, column):
if column.onupdate is None:
return None
else:
return self._exec_default(column, column.onupdate, column.type)
def _process_executemany_defaults(self):
key_getter = self.compiled._within_exec_param_key_getter
scalar_defaults = {}
insert_prefetch = self.compiled.insert_prefetch
update_prefetch = self.compiled.update_prefetch
# pre-determine scalar Python-side defaults
# to avoid many calls of get_insert_default()/
# get_update_default()
for c in insert_prefetch:
if c.default and not c.default.is_sequence and c.default.is_scalar:
scalar_defaults[c] = c.default.arg
for c in update_prefetch:
if c.onupdate and c.onupdate.is_scalar:
scalar_defaults[c] = c.onupdate.arg
for param in self.compiled_parameters:
self.current_parameters = param
for c in insert_prefetch:
if c in scalar_defaults:
val = scalar_defaults[c]
else:
val = self.get_insert_default(c)
if val is not None:
param[key_getter(c)] = val
for c in update_prefetch:
if c in scalar_defaults:
val = scalar_defaults[c]
else:
val = self.get_update_default(c)
if val is not None:
param[key_getter(c)] = val
del self.current_parameters
def _process_executesingle_defaults(self):
key_getter = self.compiled._within_exec_param_key_getter
self.current_parameters = (
compiled_parameters
) = self.compiled_parameters[0]
for c in self.compiled.insert_prefetch:
if c.default and not c.default.is_sequence and c.default.is_scalar:
val = c.default.arg
else:
val = self.get_insert_default(c)
if val is not None:
compiled_parameters[key_getter(c)] = val
for c in self.compiled.update_prefetch:
val = self.get_update_default(c)
if val is not None:
compiled_parameters[key_getter(c)] = val
del self.current_parameters
DefaultDialect.execution_ctx_cls = DefaultExecutionContext