# engine/default.py # Copyright (C) 2005-2019 the SQLAlchemy authors and contributors # # # This module is part of SQLAlchemy and is released under # the MIT License: http://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 random import re import weakref from . import interfaces from . import reflection from . import result 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 import schema 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) 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 # 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_views = True supports_sequences = False sequences_optional = False preexecute_autoincrement_sequences = False postfetch_lastrowid = True implicit_returning = False supports_right_nested_joins = True 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 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), ("pool_threadlocal", 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 = True description_encoding = None else: supports_unicode_statements = False supports_unicode_binds = False returns_unicode_strings = False description_encoding = "use_encoding" name = "default" # length at which to truncate # any identifier. max_identifier_length = 9999 _user_defined_max_identifier_length = None # length at which to truncate # the name of an index. # Usually None to indicate # 'use max_identifier_length'. # thanks to MySQL, sigh max_index_name_length = None supports_sane_rowcount = True supports_sane_multi_rowcount = True colspecs = {} default_paramstyle = "named" supports_default_values = False supports_empty_insert = True supports_multivalues_insert = False supports_server_side_cursors = False server_version_info = 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 """ @util.deprecated_params( convert_unicode=( "1.3", "The :paramref:`.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.", ) ) def __init__( self, convert_unicode=False, encoding="utf-8", paramstyle=None, dbapi=None, implicit_returning=None, supports_right_nested_joins=None, case_sensitive=True, supports_native_boolean=None, empty_in_strategy="static", max_identifier_length=None, label_length=None, **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 ) 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_right_nested_joins is not None: self.supports_right_nested_joins = supports_right_nested_joins if supports_native_boolean is not None: self.supports_native_boolean = supports_native_boolean self.case_sensitive = case_sensitive self.empty_in_strategy = empty_in_strategy if empty_in_strategy == "static": self._use_static_in = True elif empty_in_strategy in ("dynamic", "dynamic_warn"): self._use_static_in = False self._warn_on_empty_in = empty_in_strategy == "dynamic_warn" else: raise exc.ArgumentError( "empty_in_strategy may be 'static', " "'dynamic', or 'dynamic_warn'" ) 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 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) @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): return self.supports_sane_rowcount @classmethod def get_pool_class(cls, url): return getattr(cls, "poolclass", pool.QueuePool) 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_isolation_level( connection.connection ) except NotImplementedError: self.default_isolation_level = None 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): """return a callable which sets up a newly created DBAPI connection. This is used to set dialect-wide per-connection options such as isolation modes, unicode modes, etc. If a callable is returned, it will be assembled into a pool listener that receives the direct DBAPI connection, with all wrappers removed. If None is returned, no listener will be generated. """ 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 _check_unicode_returns(self, connection, additional_tests=None): 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 "conditional" else: return results == {True} def _check_unicode_description(self, connection): # all DBAPIs on Py2K return cursor.description as encoded, # until pypy2.1beta2 with sqlite, so let's just check it - # it's likely others will start doing this too in Py2k. 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 reflecttable( self, connection, table, include_columns, exclude_columns, resolve_fks, **opts ): insp = reflection.Inspector.from_engine(connection) return insp.reflecttable( table, include_columns, exclude_columns, resolve_fks, **opts ) def get_pk_constraint(self, conn, table_name, schema=None, **kw): """Compatibility method, adapts the result of get_primary_keys() for those dialects which don't implement get_pk_constraint(). """ return { "constrained_columns": self.get_primary_keys( conn, table_name, schema=schema, **kw ) } 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): return self.dbapi.connect(*cargs, **cparams) def create_connect_args(self, url): opts = url.translate_connect_args() opts.update(url.query) return [[], opts] def set_engine_execution_options(self, engine, opts): if "isolation_level" in opts: isolation_level = opts["isolation_level"] @event.listens_for(engine, "engine_connect") def set_isolation(connection, branch): if not branch: self._set_connection_isolation(connection, isolation_level) if "schema_translate_map" in opts: getter = schema._schema_getter(opts["schema_translate_map"]) engine.schema_for_object = getter @event.listens_for(engine, "engine_connect") def set_schema_translate_map(connection, branch): connection.schema_for_object = getter def set_connection_execution_options(self, connection, opts): if "isolation_level" in opts: self._set_connection_isolation(connection, opts["isolation_level"]) if "schema_translate_map" in opts: getter = schema._schema_getter(opts["schema_translate_map"]) connection.schema_for_object = getter def _set_connection_isolation(self, connection, level): if connection.in_transaction(): util.warn( "Connection is already established with a Transaction; " "setting isolation_level may implicitly rollback or commit " "the existing transaction, or have no effect until " "next transaction" ) self.set_isolation_level(connection.connection, level) connection.connection._connection_record.finalize_callback.append( self.reset_isolation_level ) 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_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 class StrCompileDialect(DefaultDialect): statement_compiler = compiler.StrSQLCompiler ddl_compiler = compiler.DDLCompiler type_compiler = compiler.StrSQLTypeCompiler preparer = compiler.IdentifierPreparer supports_sequences = True sequences_optional = True preexecute_autoincrement_sequences = False implicit_returning = False supports_native_boolean = True supports_simple_order_by_label = True 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_defaults = None _is_implicit_returning = False _is_explicit_returning = False # a hook for SQLite's translation of # result column names _translate_colname = None _expanded_parameters = util.immutabledict() @classmethod def _init_ddl(cls, dialect, connection, dbapi_connection, 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 = compiled.execution_options if connection._execution_options: self.execution_options = dict(self.execution_options) self.execution_options.update(connection._execution_options) if not dialect.supports_unicode_statements: self.unicode_statement = util.text_type(compiled) self.statement = dialect._encoder(self.unicode_statement)[0] else: self.statement = self.unicode_statement = util.text_type(compiled) 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, compiled, parameters ): """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.compiled = compiled # this should be caught in the engine before # we get here assert compiled.can_execute self.execution_options = compiled.execution_options.union( connection._execution_options ) self.result_column_struct = ( compiled._result_columns, compiled._ordered_columns, compiled._textual_ordered_columns, ) self.unicode_statement = util.text_type(compiled) if not dialect.supports_unicode_statements: self.statement = self.unicode_statement.encode( self.dialect.encoding ) else: self.statement = self.unicode_statement self.isinsert = compiled.isinsert self.isupdate = compiled.isupdate self.isdelete = compiled.isdelete self.is_text = compiled.isplaintext if not parameters: self.compiled_parameters = [compiled.construct_params()] else: self.compiled_parameters = [ compiled.construct_params(m, _group_number=grp) for grp, m in enumerate(parameters) ] self.executemany = len(parameters) > 1 self.cursor = self.create_cursor() 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 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.contains_expanding_parameters: positiontup = self._expand_in_parameters(compiled, processors) elif compiled.positional: positiontup = self.compiled.positiontup # 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 = [] for key in positiontup: if key in processors: param.append(processors[key](compiled_params[key])) else: param.append(compiled_params[key]) parameters.append(dialect.execute_sequence_format(param)) else: encode = not dialect.supports_unicode_statements for compiled_params in self.compiled_parameters: if encode: param = dict( ( dialect._encoder(key)[0], processors[key](compiled_params[key]) if key in processors else compiled_params[key], ) for key in compiled_params ) else: param = dict( ( 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 def _expand_in_parameters(self, compiled, processors): """handle special 'expanding' parameters, IN tuples that are rendered on a per-parameter basis for an otherwise fixed SQL statement string. """ if self.executemany: raise exc.InvalidRequestError( "'expanding' parameters can't be used with " "executemany()" ) if self.compiled.positional and self.compiled._numeric_binds: # I'm not familiar with any DBAPI that uses 'numeric' raise NotImplementedError( "'expanding' bind parameters not supported with " "'numeric' paramstyle at this time." ) self._expanded_parameters = {} compiled_params = self.compiled_parameters[0] if compiled.positional: positiontup = [] else: positiontup = None replacement_expressions = {} to_update_sets = {} for name in ( self.compiled.positiontup if compiled.positional else self.compiled.binds ): parameter = self.compiled.binds[name] if parameter.expanding: if name in replacement_expressions: to_update = to_update_sets[name] else: # we are removing the parameter from compiled_params # because it is a list value, which is not expected by # TypeEngine objects that would otherwise be asked to # process it. the single name is being replaced with # individual numbered parameters for each value in the # param. values = compiled_params.pop(name) if not values: to_update = to_update_sets[name] = [] replacement_expressions[ name ] = self.compiled.visit_empty_set_expr( parameter._expanding_in_types if parameter._expanding_in_types else [parameter.type] ) elif isinstance(values[0], (tuple, list)): to_update = to_update_sets[name] = [ ("%s_%s_%s" % (name, i, j), value) for i, tuple_element in enumerate(values, 1) for j, value in enumerate(tuple_element, 1) ] replacement_expressions[name] = ( "VALUES " if self.dialect.tuple_in_values else "" ) + ", ".join( "(%s)" % ", ".join( self.compiled.bindtemplate % { "name": to_update[ i * len(tuple_element) + j ][0] } for j, value in enumerate(tuple_element) ) for i, tuple_element in enumerate(values) ) else: to_update = to_update_sets[name] = [ ("%s_%s" % (name, i), value) for i, value in enumerate(values, 1) ] replacement_expressions[name] = ", ".join( self.compiled.bindtemplate % {"name": key} for key, value in to_update ) compiled_params.update(to_update) processors.update( (key, processors[name]) for key, value in to_update if name in processors ) if compiled.positional: positiontup.extend(name for name, value in to_update) self._expanded_parameters[name] = [ expand_key for expand_key, value in to_update ] elif compiled.positional: positiontup.append(name) def process_expanding(m): return replacement_expressions[m.group(1)] self.statement = re.sub( r"\[EXPANDING_(\S+)\]", process_expanding, self.statement ) return positiontup @classmethod def _init_statement( cls, dialect, connection, dbapi_connection, 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 # plain text statement self.execution_options = connection._execution_options 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): """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 = connection._execution_options self.cursor = self.create_cursor() return self @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_): """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 self.dialect.positional: default_params = self.dialect.execute_sequence_format() else: default_params = {} conn._cursor_execute(self.cursor, stmt, default_params, 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): return self.root_connection._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: 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.statement and SERVER_SIDE_CURSOR_RE.match(self.statement) ) ) ) else: use_server_side = self.execution_options.get( "stream_results", False ) return use_server_side def create_cursor(self): if self._use_server_side_cursor(): self._is_server_side = True return self.create_server_side_cursor() else: self._is_server_side = False return self._dbapi_connection.cursor() def create_server_side_cursor(self): raise NotImplementedError() def pre_exec(self): pass 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, directly after post_exec() and before the transaction is committed or ResultProxy is generated. If the post_exec() method assigns a value to `self._lastrowid`, the value is used in place of calling get_lastrowid(). Note that this method is *not* equivalent to the ``lastrowid`` method on ``ResultProxy``, which is a direct proxy to the DBAPI ``lastrowid`` accessor in all cases. """ return self.cursor.lastrowid def handle_dbapi_exception(self, e): pass def get_result_proxy(self): if self._is_server_side: return result.BufferedRowResultProxy(self) else: return result.ResultProxy(self) @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_crud_result_proxy(self): if self.isinsert and not self.executemany: if ( not self._is_implicit_returning and not self.compiled.inline and self.dialect.postfetch_lastrowid ): self._setup_ins_pk_from_lastrowid() elif not self._is_implicit_returning: self._setup_ins_pk_from_empty() result = self.get_result_proxy() if self.isinsert: if self._is_implicit_returning: row = result.fetchone() self.returned_defaults = row self._setup_ins_pk_from_implicit_returning(row) result._soft_close() result._metadata = None elif not self._is_explicit_returning: result._soft_close() result._metadata = None elif self.isupdate and self._is_implicit_returning: row = result.fetchone() self.returned_defaults = row result._soft_close() result._metadata = None elif result._metadata is None: # no results, get rowcount # (which requires open cursor on some drivers # such as kintersbasdb, mxodbc) result.rowcount result._soft_close() return result def _setup_ins_pk_from_lastrowid(self): key_getter = self.compiled._key_getters_for_crud_column[2] table = self.compiled.statement.table compiled_params = self.compiled_parameters[0] lastrowid = self.get_lastrowid() if lastrowid is not None: autoinc_col = table._autoincrement_column if autoinc_col is not None: # apply type post processors to the lastrowid proc = autoinc_col.type._cached_result_processor( self.dialect, None ) if proc is not None: lastrowid = proc(lastrowid) self.inserted_primary_key = [ lastrowid if c is autoinc_col else compiled_params.get(key_getter(c), None) for c in table.primary_key ] else: # don't have a usable lastrowid, so # do the same as _setup_ins_pk_from_empty self.inserted_primary_key = [ compiled_params.get(key_getter(c), None) for c in table.primary_key ] def _setup_ins_pk_from_empty(self): key_getter = self.compiled._key_getters_for_crud_column[2] table = self.compiled.statement.table compiled_params = self.compiled_parameters[0] self.inserted_primary_key = [ compiled_params.get(key_getter(c), None) for c in table.primary_key ] def _setup_ins_pk_from_implicit_returning(self, row): if row is None: self.inserted_primary_key = None return key_getter = self.compiled._key_getters_for_crud_column[2] table = self.compiled.statement.table compiled_params = self.compiled_parameters[0] self.inserted_primary_key = [ row[col] if value is None else value for col, value in [ (col, compiled_params.get(key_getter(col), None)) for col in table.primary_key ] ] def lastrow_has_defaults(self): return (self.isinsert or self.isupdate) and bool( self.compiled.postfetch ) def set_input_sizes( self, translate=None, include_types=None, exclude_types=None ): """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. """ if not hasattr(self.compiled, "bind_names"): return inputsizes = {} for bindparam in self.compiled.bind_names: dialect_impl = bindparam.type._unwrapped_dialect_impl(self.dialect) dialect_impl_cls = type(dialect_impl) dbtype = dialect_impl.get_dbapi_type(self.dialect.dbapi) if ( dbtype is not None and ( not exclude_types or dbtype not in exclude_types and dialect_impl_cls not in exclude_types ) and ( not include_types or dbtype in include_types or dialect_impl_cls in include_types ) ): inputsizes[bindparam] = dbtype else: inputsizes[bindparam] = None if self.dialect._has_events: self.dialect.dispatch.do_setinputsizes( inputsizes, self.cursor, self.statement, self.parameters, self ) if self.dialect.positional: positional_inputsizes = [] for key in self.compiled.positiontup: bindparam = self.compiled.binds[key] dbtype = inputsizes.get(bindparam, None) if dbtype is not None: if key in self._expanded_parameters: positional_inputsizes.extend( [dbtype] * len(self._expanded_parameters[key]) ) else: positional_inputsizes.append(dbtype) try: self.cursor.setinputsizes(*positional_inputsizes) except BaseException as e: self.root_connection._handle_dbapi_exception( e, None, None, None, self ) else: keyword_inputsizes = {} for bindparam, key in self.compiled.bind_names.items(): dbtype = inputsizes.get(bindparam, None) if dbtype is not None: if translate: # TODO: this part won't work w/ the # expanded_parameters feature, e.g. for cx_oracle # quoted bound names key = translate.get(key, key) if not self.dialect.supports_unicode_binds: key = self.dialect._encoder(key)[0] if key in self._expanded_parameters: keyword_inputsizes.update( (expand_key, dbtype) for expand_key in self._expanded_parameters[key] ) else: keyword_inputsizes[key] = dbtype try: self.cursor.setinputsizes(**keyword_inputsizes) 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: # TODO: expensive branching here should be # pulled into _exec_scalar() conn = self.connection if not default._arg_is_typed: default_arg = expression.type_coerce(default.arg, type_) else: default_arg = default.arg c = expression.select([default_arg]).compile(bind=conn) return conn._execute_compiled(c, (), {}).scalar() else: return default.arg 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:`.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:`.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:`.Column`, which is usually synonymous with the name. :param isolate_multiinsert_groups=True: indicates that multi-valued INSERT constructs created using :meth:`.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" ) if ( isolate_multiinsert_groups and self.isinsert and self.compiled.statement._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 = self.compiled.statement.parameters[0].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._key_getters_for_crud_column[2] 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 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._key_getters_for_crud_column[2] 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