# orm/mapper.py
# Copyright (C) 2005,2006 Michael Bayer mike_mp@zzzcomputing.com
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
from sqlalchemy import sql,schema,util,exceptions,logging
from sqlalchemy import sql_util
from sqlalchemy.orm import util
from sqlalchemy.orm import sync
from sqlalchemy.orm.interfaces import MapperProperty,MapperOption,OperationContext
import weakref
__all__ = ['Mapper', 'MapperExtension', 'class_mapper', 'object_mapper', 'EXT_PASS', 'mapper_registry', 'ExtensionOption']
# a dictionary mapping classes to their primary mappers
mapper_registry = weakref.WeakKeyDictionary()
# a list of MapperExtensions that will be installed in all mappers by default
global_extensions = []
# a constant returned by get_attr_by_column to indicate
# this mapper is not handling an attribute for a particular
# column
NO_ATTRIBUTE = object()
# returned by a MapperExtension method to indicate a "do nothing" response
EXT_PASS = object()
class Mapper(object):
"""Defines the correlation of class attributes to database table columns.
Instances of this class should be constructed via the sqlalchemy.orm.mapper() function."""
def __init__(self,
class_,
local_table,
properties = None,
primary_key = None,
non_primary = False,
inherits = None,
inherit_condition = None,
extension = None,
order_by = False,
allow_column_override = False,
entity_name = None,
always_refresh = False,
version_id_col = None,
polymorphic_on=None,
_polymorphic_map=None,
polymorphic_identity=None,
concrete=False,
select_table=None,
allow_null_pks=False,
batch=True,
column_prefix=None):
"""construct a new mapper.
All arguments may be sent to the sqlalchemy.orm.mapper() function where they are
passed through to here.
class_ - the class to be mapped.
local_table - the table to which the class is mapped, or None if this mapper inherits
from another mapper using concrete table inheritance.
properties - a dictionary mapping the string names of object attributes to MapperProperty
instances, which define the persistence behavior of that attribute. Note that the columns in the
mapped table are automatically converted into ColumnProperty instances based on the "key"
property of each Column (although they can be overridden using this dictionary).
primary_key - a list of Column objects which define the "primary key" to be used against this mapper's
selectable unit. This is normally simply the primary key of the "local_table", but can be overridden here.
non_primary - construct a Mapper that will define only the selection of instances, not their persistence.
inherits - another Mapper for which this Mapper will have an inheritance relationship with.
inherit_condition - for joined table inheritance, a SQL expression (constructed ClauseElement) which
will define how the two tables are joined; defaults to a natural join between the two tables.
extension - a MapperExtension instance or list of MapperExtension instances which will be applied to
all operations by this Mapper.
order_by - a single Column or list of Columns for which selection operations should use as the default
ordering for entities. Defaults to the OID/ROWID of the table if any, or the first primary key column of the table.
allow_column_override - if True, allows association relationships to be set up which override the usage of
a column that is on the table (based on key/attribute name).
entity_name - a name to be associated with the class, to allow alternate mappings for a single class.
always_refresh - if True, all query operations for this mapped class will overwrite all data
within object instances that already exist within the session, erasing any in-memory changes with whatever
information was loaded from the database.
version_id_col - a Column which must have an integer type that will be used to keep a running "version id" of
mapped entities in the database. this is used during save operations to insure that no other thread or process
has updated the instance during the lifetime of the entity, else a ConcurrentModificationError exception is thrown.
polymorphic_on - used with mappers in an inheritance relationship, a Column which will identify the class/mapper
combination to be used with a particular row. requires the polymorphic_identity value to be set for all mappers
in the inheritance hierarchy.
_polymorphic_map - used internally to propigate the full map of polymorphic identifiers to surrogate mappers.
polymorphic_identity - a value which will be stored in the Column denoted by polymorphic_on, corresponding to the
"class identity" of this mapper.
concrete - if True, indicates this mapper should use concrete table inheritance with its parent mapper.
select_table - a Table or (more commonly) Selectable which will be used to select instances of this mapper's class.
usually used to provide polymorphic loading among several classes in an inheritance hierarchy.
allow_null_pks - indicates that composite primary keys where one or more (but not all) columns contain NULL is a valid
primary key. Primary keys which contain NULL values usually indicate that a result row does not contain an entity
and should be skipped.
batch - indicates that save operations of multiple entities can be batched together for efficiency.
setting to False indicates that an instance will be fully saved before saving the next instance, which
includes inserting/updating all table rows corresponding to the entity as well as calling all MapperExtension
methods corresponding to the save operation.
column_prefix - a string which will be prepended to the "key" name of all Columns when creating column-based
properties from the given Table. does not affect explicitly specified column-based properties
"""
if not issubclass(class_, object):
raise exceptions.ArgumentError("Class '%s' is not a new-style class" % class_.__name__)
for table in (local_table, select_table):
if table is not None and isinstance(table, sql._SelectBaseMixin):
# some db's, noteably postgres, dont want to select from a select
# without an alias. also if we make our own alias internally, then
# the configured properties on the mapper are not matched against the alias
# we make, theres workarounds but it starts to get really crazy (its crazy enough
# the SQL that gets generated) so just require an alias
raise exceptions.ArgumentError("Mapping against a Select object requires that it has a name. Use an alias to give it a name, i.e. s = select(...).alias('myselect')")
self.class_ = class_
self.entity_name = entity_name
self.class_key = ClassKey(class_, entity_name)
self.primary_key = primary_key
self.non_primary = non_primary
self.order_by = order_by
self.always_refresh = always_refresh
self.version_id_col = version_id_col
self.concrete = concrete
self.single = False
self.inherits = inherits
self.select_table = select_table
self.local_table = local_table
self.inherit_condition = inherit_condition
self.extension = extension
self.properties = properties or {}
self.allow_column_override = allow_column_override
self.allow_null_pks = allow_null_pks
self.delete_orphans = []
self.batch = batch
self.column_prefix = column_prefix
# a Column which is used during a select operation to retrieve the
# "polymorphic identity" of the row, which indicates which Mapper should be used
# to construct a new object instance from that row.
self.polymorphic_on = polymorphic_on
self._eager_loaders = util.Set()
# our 'polymorphic identity', a string name that when located in a result set row
# indicates this Mapper should be used to construct the object instance for that row.
self.polymorphic_identity = polymorphic_identity
# a dictionary of 'polymorphic identity' names, associating those names with
# Mappers that will be used to construct object instances upon a select operation.
if _polymorphic_map is None:
self.polymorphic_map = {}
else:
self.polymorphic_map = _polymorphic_map
class LOrderedProp(util.OrderedProperties):
"""this extends OrderedProperties to trigger a compile() before the
members of the object are accessed."""
def _get_data(s):
self.compile()
return s.__dict__['_OrderedProperties__data']
_OrderedProperties__data = property(_get_data)
self.columns = LOrderedProp()
self.c = self.columns
# each time the options() method is called, the resulting Mapper is
# stored in this dictionary based on the given options for fast re-access
self._options = {}
# a set of all mappers which inherit from this one.
self._inheriting_mappers = util.Set()
# a second mapper that is used for selecting, if the "select_table" argument
# was sent to this mapper.
self.__surrogate_mapper = None
# whether or not our compile() method has been called already.
self.__is_compiled = False
# if this mapper is to be a primary mapper (i.e. the non_primary flag is not set),
# associate this Mapper with the given class_ and entity name. subsequent
# calls to class_mapper() for the class_/entity name combination will return this
# mapper.
self._compile_class()
self.__log("constructed")
# uncomment to compile at construction time (the old way)
# this will break mapper setups that arent declared in the order
# of dependency
#self.compile()
def __log(self, msg):
self.logger.info("(" + self.class_.__name__ + "|" + (self.entity_name is not None and "/%s" % self.entity_name or "") + (self.local_table and self.local_table.name or str(self.local_table)) + (not self._is_primary_mapper() and "|non-primary" or "") + ") " + msg)
def __log_debug(self, msg):
self.logger.debug("(" + self.class_.__name__ + "|" + (self.entity_name is not None and "/%s" % self.entity_name or "") + (self.local_table and self.local_table.name or str(self.local_table)) + (not self._is_primary_mapper() and "|non-primary" or "") + ") " + msg)
def _is_orphan(self, obj):
optimistic = has_identity(obj)
for (key,klass) in self.delete_orphans:
if getattr(klass, key).hasparent(obj, optimistic=optimistic):
return False
else:
if len(self.delete_orphans):
if not has_identity(obj):
raise exceptions.FlushError("instance %s is an unsaved, pending instance and is an orphan (is not attached to %s)" %
(
obj,
", nor ".join(["any parent '%s' instance via that classes' '%s' attribute" % (klass.__name__, key) for (key,klass) in self.delete_orphans])
))
else:
return True
else:
return False
def _get_props(self):
self.compile()
return self.__props
props = property(_get_props, doc="compiles this mapper if needed, and returns the \
dictionary of MapperProperty objects associated with this mapper.")
def compile(self):
"""compile this mapper into its final internal format.
this is the 'external' version of the method which is not reentrant."""
if self.__is_compiled:
return self
self._compile_all()
# if we're not primary, compile us
if self.non_primary:
self._do_compile()
self._initialize_properties()
return self
def _compile_all(self):
# compile all primary mappers
for mapper in mapper_registry.values():
if not mapper.__is_compiled:
mapper._do_compile()
# initialize properties on all mappers
for mapper in mapper_registry.values():
if not mapper.__props_init:
mapper._initialize_properties()
def _check_compile(self):
if self.non_primary:
self._do_compile()
self._initialize_properties()
return self
def _do_compile(self):
"""compile this mapper into its final internal format.
this is the 'internal' version of the method which is assumed to be called within compile()
and is reentrant.
"""
if self.__is_compiled:
return self
self.__log("_do_compile() started")
self.__is_compiled = True
self.__props_init = False
self._compile_extensions()
self._compile_inheritance()
self._compile_tables()
self._compile_properties()
self._compile_selectable()
self.__log("_do_compile() complete")
return self
def _compile_extensions(self):
"""goes through the global_extensions list as well as the list of MapperExtensions
specified for this Mapper and creates a linked list of those extensions."""
extlist = util.Set()
for ext_class in global_extensions:
if isinstance(ext_class, MapperExtension):
extlist.add(ext_class)
else:
extlist.add(ext_class())
extension = self.extension
if extension is not None:
for ext_obj in util.to_list(extension):
extlist.add(ext_obj)
self.extension = _ExtensionCarrier()
for ext in extlist:
self.extension.append(ext)
def _compile_inheritance(self):
"""determines if this Mapper inherits from another mapper, and if so calculates the mapped_table
for this Mapper taking the inherited mapper into account. for joined table inheritance, creates
a SyncRule that will synchronize column values between the joined tables. also initializes polymorphic variables
used in polymorphic loads."""
if self.inherits is not None:
if isinstance(self.inherits, type):
self.inherits = class_mapper(self.inherits, compile=False)._do_compile()
else:
self.inherits = self.inherits._do_compile()
if not issubclass(self.class_, self.inherits.class_):
raise exceptions.ArgumentError("Class '%s' does not inherit from '%s'" % (self.class_.__name__, self.inherits.class_.__name__))
if self._is_primary_mapper() != self.inherits._is_primary_mapper():
np = self._is_primary_mapper() and "primary" or "non-primary"
raise exceptions.ArgumentError("Inheritance of %s mapper for class '%s' is only allowed from a %s mapper" % (np, self.class_.__name__, np))
# inherit_condition is optional.
if self.local_table is None:
self.local_table = self.inherits.local_table
self.single = True
if not self.local_table is self.inherits.local_table:
if self.concrete:
self._synchronizer= None
self.mapped_table = self.local_table
else:
if self.inherit_condition is None:
# figure out inherit condition from our table to the immediate table
# of the inherited mapper, not its full table which could pull in other
# stuff we dont want (allows test/inheritance.InheritTest4 to pass)
self.inherit_condition = sql.join(self.inherits.local_table, self.local_table).onclause
self.mapped_table = sql.join(self.inherits.mapped_table, self.local_table, self.inherit_condition)
# generate sync rules. similarly to creating the on clause, specify a
# stricter set of tables to create "sync rules" by,based on the immediate
# inherited table, rather than all inherited tables
self._synchronizer = sync.ClauseSynchronizer(self, self, sync.ONETOMANY)
self._synchronizer.compile(self.mapped_table.onclause)
else:
self._synchronizer = None
self.mapped_table = self.local_table
if self.polymorphic_identity is not None:
self.inherits._add_polymorphic_mapping(self.polymorphic_identity, self)
if self.polymorphic_on is None and self.inherits.polymorphic_on is not None:
self.polymorphic_on = self.mapped_table.corresponding_column(self.inherits.polymorphic_on, keys_ok=True, raiseerr=False)
if self.order_by is False:
self.order_by = self.inherits.order_by
self.polymorphic_map = self.inherits.polymorphic_map
self.batch = self.inherits.batch
self.inherits._inheriting_mappers.add(self)
else:
self._synchronizer = None
self.mapped_table = self.local_table
if self.polymorphic_identity is not None:
self._add_polymorphic_mapping(self.polymorphic_identity, self)
if self.mapped_table is None:
raise exceptions.ArgumentError("Mapper '%s' does not have a mapped_table specified. (Are you using the return value of table.create()? It no longer has a return value.)" % str(self))
# convert polymorphic class associations to mappers
for key in self.polymorphic_map.keys():
if isinstance(self.polymorphic_map[key], type):
self.polymorphic_map[key] = class_mapper(self.polymorphic_map[key])
def _add_polymorphic_mapping(self, key, class_or_mapper, entity_name=None):
"""adds a Mapper to our 'polymorphic map' """
if isinstance(class_or_mapper, type):
class_or_mapper = class_mapper(class_or_mapper, entity_name=entity_name)
self.polymorphic_map[key] = class_or_mapper
def _compile_tables(self):
"""after the inheritance relationships have been reconciled, sets up some more table-based instance
variables and determines the "primary key" columns for all tables represented by this Mapper."""
# summary of the various Selectable units:
# mapped_table - the Selectable that represents a join of the underlying Tables to be saved (or just the Table)
# local_table - the Selectable that was passed to this Mapper's constructor, if any
# select_table - the Selectable that will be used during queries. if this is specified
# as a constructor keyword argument, it takes precendence over mapped_table, otherwise its mapped_table
# unjoined_table - our Selectable, minus any joins constructed against the inherits table.
# this is either select_table if it was given explicitly, or in the case of a mapper that inherits
# its local_table
# tables - a collection of underlying Table objects pulled from mapped_table
if self.select_table is None:
self.select_table = self.mapped_table
self.unjoined_table = self.local_table
# locate all tables contained within the "table" passed in, which
# may be a join or other construct
self.tables = sqlutil.TableFinder(self.mapped_table)
# determine primary key columns, either passed in, or get them from our set of tables
self.pks_by_table = {}
if self.primary_key is not None:
# determine primary keys using user-given list of primary key columns as a guide
#
# TODO: this might not work very well for joined-table and/or polymorphic
# inheritance mappers since local_table isnt taken into account nor is select_table
# need to test custom primary key columns used with inheriting mappers
for k in self.primary_key:
self.pks_by_table.setdefault(k.table, util.OrderedSet()).add(k)
if k.table != self.mapped_table:
# associate pk cols from subtables to the "main" table
self.pks_by_table.setdefault(self.mapped_table, util.OrderedSet()).add(k)
else:
# no user-defined primary key columns - go through all of our represented tables
# and assemble primary key columns
for t in self.tables + [self.mapped_table]:
try:
l = self.pks_by_table[t]
except KeyError:
l = self.pks_by_table.setdefault(t, util.OrderedSet())
for k in t.primary_key:
#if k.key not in t.c and k._label not in t.c:
# this is a condition that was occurring when table reflection was doubling up primary keys
# that were overridden in the Table constructor
# raise exceptions.AssertionError("Column " + str(k) + " not located in the column set of table " + str(t))
l.add(k)
if len(self.pks_by_table[self.mapped_table]) == 0:
raise exceptions.ArgumentError("Could not assemble any primary key columns for mapped table '%s'" % (self.mapped_table.name))
def _compile_properties(self):
"""inspects the properties dictionary sent to the Mapper's constructor as well as the mapped_table, and creates
MapperProperty objects corresponding to each mapped column and relation. also grabs MapperProperties from the
inherited mapper, if any, and creates copies of them to attach to this Mapper."""
# object attribute names mapped to MapperProperty objects
self.__props = {}
# table columns mapped to lists of MapperProperty objects
# using a list allows a single column to be defined as
# populating multiple object attributes
self.columntoproperty = mapperutil.TranslatingDict(self.mapped_table)
# load custom properties
if self.properties is not None:
for key, prop in self.properties.iteritems():
self._compile_property(key, prop, False)
if self.inherits is not None:
for key, prop in self.inherits.__props.iteritems():
if not self.__props.has_key(key):
prop.adapt_to_inherited(key, self)
# load properties from the main table object,
# not overriding those set up in the 'properties' argument
for column in self.mapped_table.columns:
if self.columntoproperty.has_key(column):
continue
if not self.columns.has_key(column.key):
self.columns[column.key] = self.select_table.corresponding_column(column, keys_ok=True, raiseerr=True)
column_key = (self.column_prefix or '') + column.key
prop = self.__props.get(column.key, None)
if prop is None:
prop = ColumnProperty(column)
self.__props[column_key] = prop
prop.set_parent(self)
self.__log("adding ColumnProperty %s" % (column_key))
elif isinstance(prop, ColumnProperty):
if prop.parent is not self:
prop = ColumnProperty(deferred=prop.deferred, group=prop.group, *prop.columns)
prop.set_parent(self)
self.__props[column_key] = prop
prop.columns.append(column)
self.__log("appending to existing ColumnProperty %s" % (column_key))
else:
if not self.allow_column_override:
raise exceptions.ArgumentError("WARNING: column '%s' not being added due to property '%s'. Specify 'allow_column_override=True' to mapper() to ignore this condition." % (column.key, repr(prop)))
else:
continue
# its a ColumnProperty - match the ultimate table columns
# back to the property
proplist = self.columntoproperty.setdefault(column, [])
proplist.append(prop)
def _initialize_properties(self):
"""calls the init() method on all MapperProperties attached to this mapper. this will incur the
compilation of related mappers."""
self.__log("_initialize_properties() started")
l = [(key, prop) for key, prop in self.__props.iteritems()]
for key, prop in l:
if getattr(prop, 'key', None) is None:
prop.init(key, self)
self.__log("_initialize_properties() complete")
self.__props_init = True
def _compile_selectable(self):
"""if the 'select_table' keyword argument was specified,
set up a second "surrogate mapper" that will be used for select operations.
the columns of select_table should encompass all the columns of the mapped_table either directly
or through proxying relationships."""
if self.select_table is not self.mapped_table:
props = {}
if self.properties is not None:
for key, prop in self.properties.iteritems():
if sql.is_column(prop):
props[key] = self.select_table.corresponding_column(prop)
elif (isinstance(prop, list) and sql.is_column(prop[0])):
props[key] = [self.select_table.corresponding_column(c) for c in prop]
self.__surrogate_mapper = Mapper(self.class_, self.select_table, non_primary=True, properties=props, _polymorphic_map=self.polymorphic_map, polymorphic_on=self.select_table.corresponding_column(self.polymorphic_on))
def _compile_class(self):
"""if this mapper is to be a primary mapper (i.e. the non_primary flag is not set),
associate this Mapper with the given class_ and entity name. subsequent
calls to class_mapper() for the class_/entity name combination will return this
mapper. also decorates the __init__ method on the mapped class to include auto-session attachment logic."""
if self.non_primary:
return
if not self.non_primary and (mapper_registry.has_key(self.class_key)):
raise exceptions.ArgumentError("Class '%s' already has a primary mapper defined with entity name '%s'. Use non_primary=True to create a non primary Mapper, or to create a new primary mapper, remove this mapper first via sqlalchemy.orm.clear_mapper(mapper), or preferably sqlalchemy.orm.clear_mappers() to clear all mappers." % (self.class_, self.entity_name))
attribute_manager.reset_class_managed(self.class_)
oldinit = self.class_.__init__
def init(self, *args, **kwargs):
entity_name = kwargs.pop('_sa_entity_name', None)
mapper = mapper_registry.get(ClassKey(self.__class__, entity_name))
if mapper is not None:
mapper = mapper.compile()
# this gets the AttributeManager to do some pre-initialization,
# in order to save on KeyErrors later on
attribute_manager.init_attr(self)
if kwargs.has_key('_sa_session'):
session = kwargs.pop('_sa_session')
else:
# works for whatever mapper the class is associated with
if mapper is not None:
session = mapper.extension.get_session()
if session is EXT_PASS:
session = None
else:
session = None
# if a session was found, either via _sa_session or via mapper extension,
# and we have found a mapper, save() this instance to the session, and give it an associated entity_name.
# otherwise, this instance will not have a session or mapper association until it is
# save()d to some session.
if session is not None and mapper is not None:
self._entity_name = entity_name
session._register_pending(self)
if oldinit is not None:
try:
oldinit(self, *args, **kwargs)
except:
if session is not None:
session.expunge(self)
raise
# override oldinit, insuring that its not already a Mapper-decorated init method
if oldinit is None or not hasattr(oldinit, '_sa_mapper_init'):
init._sa_mapper_init = True
try:
init.__name__ = oldinit.__name__
init.__doc__ = oldinit.__doc__
except:
# cant set __name__ in py 2.3 !
pass
self.class_.__init__ = init
mapper_registry[self.class_key] = self
if self.entity_name is None:
self.class_.c = self.c
def base_mapper(self):
"""return the ultimate base mapper in an inheritance chain"""
if self.inherits is not None:
return self.inherits.base_mapper()
else:
return self
def common_parent(self, other):
"""return true if the given mapper shares a common inherited parent as this mapper"""
return self.base_mapper() is other.base_mapper()
def isa(self, other):
"""return True if the given mapper inherits from this mapper"""
m = other
while m is not self and m.inherits is not None:
m = m.inherits
return m is self
def iterate_to_root(self):
m = self
while m is not None:
yield m
m = m.inherits
def polymorphic_iterator(self):
"""iterates through the collection including this mapper and all descendant mappers.
this includes not just the immediately inheriting mappers but all their inheriting mappers as well.
To iterate through an entire hierarchy, use mapper.base_mapper().polymorphic_iterator()."""
def iterate(m):
yield m
for mapper in m._inheriting_mappers:
for x in iterate(mapper):
yield x
return iterate(self)
def add_properties(self, dict_of_properties):
"""adds the given dictionary of properties to this mapper, using add_property."""
for key, value in dict_of_properties.iteritems():
self.add_property(key, value)
def add_property(self, key, prop):
"""add an indiviual MapperProperty to this mapper.
If the mapper has not been compiled yet, just adds the property to the initial
properties dictionary sent to the constructor. if this Mapper
has already been compiled, then the given MapperProperty is compiled immediately."""
self.properties[key] = prop
if self.__is_compiled:
# if we're compiled, make sure all the other mappers are compiled too
self._compile_all()
self._compile_property(key, prop, init=True)
def _create_prop_from_column(self, column, skipmissing=False):
if sql.is_column(column):
try:
column = self.mapped_table.corresponding_column(column)
except KeyError:
if skipmissing:
return
raise exceptions.ArgumentError("Column '%s' is not represented in mapper's table" % prop._label)
return ColumnProperty(column)
elif isinstance(column, list) and sql.is_column(column[0]):
try:
column = [self.mapped_table.corresponding_column(c) for c in column]
except KeyError, e:
# TODO: want to take the columns we have from this
if skipmissing:
return
raise exceptions.ArgumentError("Column '%s' is not represented in mapper's table" % e.args[0])
return ColumnProperty(*column)
else:
return None
def _compile_property(self, key, prop, init=True, skipmissing=False, setparent=True):
"""add a MapperProperty to this or another Mapper, including configuration of the property.
The properties' parent attribute will be set, and the property will also be
copied amongst the mappers which inherit from this one.
if the given prop is a Column or list of Columns, a ColumnProperty will be created.
"""
self.__log("_compile_property(%s, %s)" % (key, prop.__class__.__name__))
if not isinstance(prop, MapperProperty):
prop = self._create_prop_from_column(prop, skipmissing=skipmissing)
if prop is None:
raise exceptions.ArgumentError("'%s' is not an instance of MapperProperty or Column" % repr(prop))
self.__props[key] = prop
if setparent:
prop.set_parent(self)
if isinstance(prop, ColumnProperty):
col = self.select_table.corresponding_column(prop.columns[0], keys_ok=True, raiseerr=False)
if col is None:
col = prop.columns[0]
self.columns[key] = col
for col in prop.columns:
proplist = self.columntoproperty.setdefault(col, [])
proplist.append(prop)
if init:
prop.init(key, self)
for mapper in self._inheriting_mappers:
prop.adapt_to_inherited(key, mapper)
def __str__(self):
return "Mapper|" + self.class_.__name__ + "|" + (self.entity_name is not None and "/%s" % self.entity_name or "") + (self.local_table and self.local_table.name or str(self.local_table)) + (not self._is_primary_mapper() and "|non-primary" or "")
def _is_primary_mapper(self):
"""returns True if this mapper is the primary mapper for its class key (class + entity_name)"""
return mapper_registry.get(self.class_key, None) is self
def primary_mapper(self):
"""returns the primary mapper corresponding to this mapper's class key (class + entity_name)"""
return mapper_registry[self.class_key]
def is_assigned(self, instance):
"""return True if this mapper handles the given instance.
this is dependent not only on class assignment but the optional "entity_name" parameter as well."""
return instance.__class__ is self.class_ and getattr(instance, '_entity_name', None) == self.entity_name
def _assign_entity_name(self, instance):
"""assign this Mapper's entity name to the given instance.
subsequent Mapper lookups for this instance will return the primary
mapper corresponding to this Mapper's class and entity name."""
instance._entity_name = self.entity_name
def get_session(self):
"""return the contextual session provided by the mapper extension chain, if any.
raises InvalidRequestError if a session cannot be retrieved from the extension chain
"""
self.compile()
s = self.extension.get_session()
if s is EXT_PASS:
raise exceptions.InvalidRequestError("No contextual Session is established. Use a MapperExtension that implements get_session or use 'import sqlalchemy.mods.threadlocal' to establish a default thread-local contextual session.")
return s
def has_eager(self):
"""return True if one of the properties attached to this Mapper is eager loading"""
return len(self._eager_loaders) > 0
def instances(self, cursor, session, *mappers, **kwargs):
"""return a list of mapped instances corresponding to the rows in a given ResultProxy."""
import sqlalchemy.orm.query
return sqlalchemy.orm.Query(self, session).instances(cursor, *mappers, **kwargs)
def identity_key_from_row(self, row):
"""return an identity-map key for use in storing/retrieving an item from the identity map.
row - a sqlalchemy.dbengine.RowProxy instance or other map corresponding result-set
column names to their values within a row.
"""
return (self.class_, tuple([row[column] for column in self.pks_by_table[self.mapped_table]]), self.entity_name)
def identity_key_from_primary_key(self, primary_key):
"""return an identity-map key for use in storing/retrieving an item from an identity map.
primary_key - a list of values indicating the identifier.
"""
return (self.class_, tuple(util.to_list(primary_key)), self.entity_name)
def identity_key_from_instance(self, instance):
"""return the identity key for the given instance, based on its primary key attributes.
this value is typically also found on the instance itself under the attribute name '_instance_key'.
"""
return self.identity_key_from_primary_key(self.primary_key_from_instance(instance))
def primary_key_from_instance(self, instance):
"""return the list of primary key values for the given instance."""
return [self.get_attr_by_column(instance, column) for column in self.pks_by_table[self.mapped_table]]
def instance_key(self, instance):
"""deprecated. a synonym for identity_key_from_instance."""
return self.identity_key_from_instance(instance)
def identity_key(self, primary_key):
"""deprecated. a synonym for identity_key_from_primary_key."""
return self.identity_key_from_primary_key(primary_key)
def identity(self, instance):
"""deprecated. a synoynm for primary_key_from_instance."""
return self.primary_key_from_instance(instance)
def _getpropbycolumn(self, column, raiseerror=True):
try:
prop = self.columntoproperty[column]
except KeyError:
try:
prop = self.__props[column.key]
if not raiseerror:
return None
raise exceptions.InvalidRequestError("Column '%s.%s' is not available, due to conflicting property '%s':%s" % (column.table.name, column.name, column.key, repr(prop)))
except KeyError:
if not raiseerror:
return None
raise exceptions.InvalidRequestError("No column %s.%s is configured on mapper %s..." % (column.table.name, column.name, str(self)))
return prop[0]
def get_attr_by_column(self, obj, column, raiseerror=True):
"""return an instance attribute using a Column as the key."""
prop = self._getpropbycolumn(column, raiseerror)
if prop is None:
return NO_ATTRIBUTE
#self.__log_debug("get column attribute '%s' from instance %s" % (column.key, mapperutil.instance_str(obj)))
return prop.getattr(obj)
def set_attr_by_column(self, obj, column, value):
"""set the value of an instance attribute using a Column as the key."""
self.columntoproperty[column][0].setattr(obj, value)
def save_obj(self, objects, uowtransaction, postupdate=False, post_update_cols=None, single=False):
"""issue INSERT and/or UPDATE statements for a list of objects.
this is called within the context of a UOWTransaction during a flush operation.
save_obj issues SQL statements not just for instances mapped directly by this mapper, but
for instances mapped by all inheriting mappers as well. This is to maintain proper insert
ordering among a polymorphic chain of instances. Therefore save_obj is typically
called only on a "base mapper", or a mapper which does not inherit from any other mapper."""
self.__log_debug("save_obj() start, " + (single and "non-batched" or "batched"))
# if batch=false, call save_obj separately for each object
if not single and not self.batch:
for obj in objects:
self.save_obj([obj], uowtransaction, postupdate=postupdate, post_update_cols=post_update_cols, single=True)
return
connection = uowtransaction.transaction.connection(self)
if not postupdate:
for obj in objects:
if not has_identity(obj):
for mapper in object_mapper(obj).iterate_to_root():
mapper.extension.before_insert(mapper, connection, obj)
else:
for mapper in object_mapper(obj).iterate_to_root():
mapper.extension.before_update(mapper, connection, obj)
for obj in objects:
# detect if we have a "pending" instance (i.e. has no instance_key attached to it),
# and another instance with the same identity key already exists as persistent. convert to an
# UPDATE if so.
mapper = object_mapper(obj)
instance_key = mapper.instance_key(obj)
is_row_switch = not postupdate and not has_identity(obj) and instance_key in uowtransaction.uow.identity_map
if is_row_switch:
existing = uowtransaction.uow.identity_map[instance_key]
if not uowtransaction.is_deleted(existing):
raise exceptions.FlushError("New instance %s with identity key %s conflicts with persistent instance %s" % (mapperutil.instance_str(obj), str(instance_key), mapperutil.instance_str(existing)))
self.__log_debug("detected row switch for identity %s. will update %s, remove %s from transaction" % (instance_key, mapperutil.instance_str(obj), mapperutil.instance_str(existing)))
uowtransaction.unregister_object(existing)
inserted_objects = util.Set()
updated_objects = util.Set()
table_to_mapper = {}
for mapper in self.base_mapper().polymorphic_iterator():
for t in mapper.tables:
table_to_mapper.setdefault(t, mapper)
for table in sqlutil.TableCollection(list(table_to_mapper.keys())).sort(reverse=False):
# two lists to store parameters for each table/object pair located
insert = []
update = []
for obj in objects:
mapper = object_mapper(obj)
if table not in mapper.tables or not mapper._has_pks(table):
continue
instance_key = mapper.instance_key(obj)
self.__log_debug("save_obj() table '%s' instance %s identity %s" % (table.name, mapperutil.instance_str(obj), str(instance_key)))
isinsert = not instance_key in uowtransaction.uow.identity_map and not postupdate and not has_identity(obj)
params = {}
hasdata = False
for col in table.columns:
if col is mapper.version_id_col:
if not isinsert:
params[col._label] = mapper.get_attr_by_column(obj, col)
params[col.key] = params[col._label] + 1
else:
params[col.key] = 1
elif col in mapper.pks_by_table[table]:
# column is a primary key ?
if not isinsert:
# doing an UPDATE? put primary key values as "WHERE" parameters
# matching the bindparam we are creating below, i.e. "<tablename>_<colname>"
params[col._label] = mapper.get_attr_by_column(obj, col)
else:
# doing an INSERT, primary key col ?
# if the primary key values are not populated,
# leave them out of the INSERT altogether, since PostGres doesn't want
# them to be present for SERIAL to take effect. A SQLEngine that uses
# explicit sequences will put them back in if they are needed
value = mapper.get_attr_by_column(obj, col)
if value is not None:
params[col.key] = value
elif mapper.polymorphic_on is not None and mapper.polymorphic_on.shares_lineage(col):
if isinsert:
self.__log_debug("Using polymorphic identity '%s' for insert column '%s'" % (mapper.polymorphic_identity, col.key))
value = mapper.polymorphic_identity
if col.default is None or value is not None:
params[col.key] = value
else:
# column is not a primary key ?
if not isinsert:
# doing an UPDATE ? get the history for the attribute, with "passive"
# so as not to trigger any deferred loads. if there is a new
# value, add it to the bind parameters
if post_update_cols is not None and col not in post_update_cols:
continue
elif is_row_switch:
params[col.key] = self.get_attr_by_column(obj, col)
hasdata = True
continue
prop = mapper._getpropbycolumn(col, False)
if prop is None:
continue
history = prop.get_history(obj, passive=True)
if history:
a = history.added_items()
if len(a):
params[col.key] = a[0]
hasdata = True
else:
# doing an INSERT, non primary key col ?
# add the attribute's value to the
# bind parameters, unless its None and the column has a
# default. if its None and theres no default, we still might
# not want to put it in the col list but SQLIte doesnt seem to like that
# if theres no columns at all
value = mapper.get_attr_by_column(obj, col, False)
if value is NO_ATTRIBUTE:
continue
if col.default is None or value is not None:
params[col.key] = value
if not isinsert:
if hasdata:
# if none of the attributes changed, dont even
# add the row to be updated.
update.append((obj, params, mapper))
else:
insert.append((obj, params, mapper))
if len(update):
mapper = table_to_mapper[table]
clause = sql.and_()
for col in mapper.pks_by_table[table]:
clause.clauses.append(col == sql.bindparam(col._label, type=col.type))
if mapper.version_id_col is not None:
clause.clauses.append(mapper.version_id_col == sql.bindparam(mapper.version_id_col._label, type=col.type))
statement = table.update(clause)
rows = 0
supports_sane_rowcount = True
def comparator(a, b):
for col in mapper.pks_by_table[table]:
x = cmp(a[1][col._label],b[1][col._label])
if x != 0:
return x
return 0
update.sort(comparator)
for rec in update:
(obj, params, mapper) = rec
c = connection.execute(statement, params)
mapper._postfetch(connection, table, obj, c, c.last_updated_params())
updated_objects.add(obj)
rows += c.cursor.rowcount
if c.supports_sane_rowcount() and rows != len(update):
raise exceptions.ConcurrentModificationError("Updated rowcount %d does not match number of objects updated %d" % (rows, len(update)))
if len(insert):
statement = table.insert()
def comparator(a, b):
return cmp(a[0]._sa_insert_order, b[0]._sa_insert_order)
insert.sort(comparator)
for rec in insert:
(obj, params, mapper) = rec
c = connection.execute(statement, params)
primary_key = c.last_inserted_ids()
if primary_key is not None:
i = 0
for col in mapper.pks_by_table[table]:
if mapper.get_attr_by_column(obj, col) is None and len(primary_key) > i:
mapper.set_attr_by_column(obj, col, primary_key[i])
i+=1
mapper._postfetch(connection, table, obj, c, c.last_inserted_params())
# synchronize newly inserted ids from one table to the next
# TODO: this fires off more than needed, try to organize syncrules
# per table
def sync(mapper):
inherit = mapper.inherits
if inherit is not None:
sync(inherit)
if mapper._synchronizer is not None:
mapper._synchronizer.execute(obj, obj)
sync(mapper)
inserted_objects.add(obj)
if not postupdate:
for obj in inserted_objects:
for mapper in object_mapper(obj).iterate_to_root():
mapper.extension.after_insert(mapper, connection, obj)
for obj in updated_objects:
for mapper in object_mapper(obj).iterate_to_root():
mapper.extension.after_update(mapper, connection, obj)
def _postfetch(self, connection, table, obj, resultproxy, params):
"""after an INSERT or UPDATE, asks the returned result if PassiveDefaults fired off on the database side
which need to be post-fetched, *or* if pre-exec defaults like ColumnDefaults were fired off
and should be populated into the instance. this is only for non-primary key columns."""
if resultproxy.lastrow_has_defaults():
clause = sql.and_()
for p in self.pks_by_table[table]:
clause.clauses.append(p == self.get_attr_by_column(obj, p))
row = connection.execute(table.select(clause), None).fetchone()
for c in table.c:
if self.get_attr_by_column(obj, c, False) is None:
self.set_attr_by_column(obj, c, row[c])
else:
for c in table.c:
if c.primary_key or not params.has_key(c.name):
continue
v = self.get_attr_by_column(obj, c, False)
if v is NO_ATTRIBUTE:
continue
elif v != params.get_original(c.name):
self.set_attr_by_column(obj, c, params.get_original(c.name))
def delete_obj(self, objects, uowtransaction):
"""issue DELETE statements for a list of objects.
this is called within the context of a UOWTransaction during a flush operation."""
self.__log_debug("delete_obj() start")
connection = uowtransaction.transaction.connection(self)
[self.extension.before_delete(self, connection, obj) for obj in objects]
deleted_objects = util.Set()
for table in self.tables.sort(reverse=True):
if not self._has_pks(table):
continue
delete = []
for obj in objects:
params = {}
if not hasattr(obj, "_instance_key"):
continue
else:
delete.append(params)
for col in self.pks_by_table[table]:
params[col.key] = self.get_attr_by_column(obj, col)
if self.version_id_col is not None:
params[self.version_id_col.key] = self.get_attr_by_column(obj, self.version_id_col)
deleted_objects.add(obj)
if len(delete):
def comparator(a, b):
for col in self.pks_by_table[table]:
x = cmp(a[col.key],b[col.key])
if x != 0:
return x
return 0
delete.sort(comparator)
clause = sql.and_()
for col in self.pks_by_table[table]:
clause.clauses.append(col == sql.bindparam(col.key, type=col.type))
if self.version_id_col is not None:
clause.clauses.append(self.version_id_col == sql.bindparam(self.version_id_col.key, type=self.version_id_col.type))
statement = table.delete(clause)
c = connection.execute(statement, delete)
if c.supports_sane_rowcount() and c.rowcount != len(delete):
raise exceptions.ConcurrentModificationError("Updated rowcount %d does not match number of objects updated %d" % (c.cursor.rowcount, len(delete)))
[self.extension.after_delete(self, connection, obj) for obj in deleted_objects]
def _has_pks(self, table):
try:
for k in self.pks_by_table[table]:
if not self.columntoproperty.has_key(k):
return False
else:
return True
except KeyError:
return False
def register_dependencies(self, uowcommit, *args, **kwargs):
"""register DependencyProcessor instances with a unitofwork.UOWTransaction.
this calls register_dependencies on all attached MapperProperty instances."""
for prop in self.__props.values():
prop.register_dependencies(uowcommit, *args, **kwargs)
def cascade_iterator(self, type, object, recursive=None):
"""iterate each element in an object graph, for all relations taht meet the given cascade rule.
type - the name of the cascade rule (i.e. save-update, delete, etc.)
object - the lead object instance. child items will be processed per the relations
defined for this object's mapper.
recursive - used by the function for internal context during recursive calls, leave as None."""
if recursive is None:
recursive=util.Set()
for prop in self.__props.values():
for c in prop.cascade_iterator(type, object, recursive):
yield c
def cascade_callable(self, type, object, callable_, recursive=None):
"""execute a callable for each element in an object graph, for all relations that meet the given cascade rule.
type - the name of the cascade rule (i.e. save-update, delete, etc.)
object - the lead object instance. child items will be processed per the relations
defined for this object's mapper.
callable_ - the callable function.
recursive - used by the function for internal context during recursive calls, leave as None."""
if recursive is None:
recursive=util.Set()
for prop in self.__props.values():
prop.cascade_callable(type, object, callable_, recursive)
def get_select_mapper(self):
"""return the mapper used for issuing selects.
this mapper is the same mapper as 'self' unless the select_table argument was specified for this mapper."""
return self.__surrogate_mapper or self
def _instance(self, context, row, result = None):
"""pulls an object instance from the given row and appends it to the given result
list. if the instance already exists in the given identity map, its not added. in
either case, executes all the property loaders on the instance to also process extra
information in the row."""
if self.polymorphic_on is not None:
discriminator = row[self.polymorphic_on]
mapper = self.polymorphic_map[discriminator]
if mapper is not self:
row = self.translate_row(mapper, row)
return mapper._instance(context, row, result=result)
# look in main identity map. if its there, we dont do anything to it,
# including modifying any of its related items lists, as its already
# been exposed to being modified by the application.
populate_existing = context.populate_existing or self.always_refresh
identitykey = self.identity_key_from_row(row)
if context.session.has_key(identitykey):
instance = context.session._get(identitykey)
self.__log_debug("_instance(): using existing instance %s identity %s" % (mapperutil.instance_str(instance), str(identitykey)))
isnew = False
if context.version_check and self.version_id_col is not None and self.get_attr_by_column(instance, self.version_id_col) != row[self.version_id_col]:
raise exceptions.ConcurrentModificationError("Instance '%s' version of %s does not match %s" % (instance, self.get_attr_by_column(instance, self.version_id_col), row[self.version_id_col]))
if populate_existing or context.session.is_expired(instance, unexpire=True):
if not context.identity_map.has_key(identitykey):
context.identity_map[identitykey] = instance
if self.extension.populate_instance(self, context, row, instance, identitykey, True) is EXT_PASS:
self.populate_instance(context, instance, row, identitykey, True)
if self.extension.append_result(self, context, row, instance, identitykey, result, isnew) is EXT_PASS:
if result is not None:
result.append(instance)
return instance
else:
self.__log_debug("_instance(): identity key %s not in session" % str(identitykey) + repr([mapperutil.instance_str(x) for x in context.session]))
# look in result-local identitymap for it.
exists = context.identity_map.has_key(identitykey)
if not exists:
if self.allow_null_pks:
# check if *all* primary key cols in the result are None - this indicates
# an instance of the object is not present in the row.
for col in self.pks_by_table[self.mapped_table]:
if row[col] is not None:
break
else:
return None
else:
# otherwise, check if *any* primary key cols in the result are None - this indicates
# an instance of the object is not present in the row.
for col in self.pks_by_table[self.mapped_table]:
if row[col] is None:
return None
# plugin point
instance = self.extension.create_instance(self, context, row, self.class_)
if instance is EXT_PASS:
instance = self._create_instance(context.session)
self.__log_debug("_instance(): created new instance %s identity %s" % (mapperutil.instance_str(instance), str(identitykey)))
context.identity_map[identitykey] = instance
isnew = True
else:
instance = context.identity_map[identitykey]
isnew = False
# call further mapper properties on the row, to pull further
# instances from the row and possibly populate this item.
if self.extension.populate_instance(self, context, row, instance, identitykey, isnew) is EXT_PASS:
self.populate_instance(context, instance, row, identitykey, isnew)
if self.extension.append_result(self, context, row, instance, identitykey, result, isnew) is EXT_PASS:
if result is not None:
result.append(instance)
return instance
def _create_instance(self, session):
obj = self.class_.__new__(self.class_)
obj._entity_name = self.entity_name
# this gets the AttributeManager to do some pre-initialization,
# in order to save on KeyErrors later on
attribute_manager.init_attr(obj)
return obj
def translate_row(self, tomapper, row):
"""translate the column keys of a row into a new or proxied row that
can be understood by another mapper.
This can be used in conjunction with populate_instance to populate
an instance using an alternate mapper."""
newrow = util.DictDecorator(row)
for c in tomapper.mapped_table.c:
c2 = self.mapped_table.corresponding_column(c, keys_ok=True, raiseerr=True)
if row.has_key(c2):
newrow[c] = row[c2]
return newrow
def populate_instance(self, selectcontext, instance, row, identitykey, isnew):
"""populate an instance from a result row.
This method iterates through the list of MapperProperty objects attached to this Mapper
and calls each properties execute() method."""
for prop in self.__props.values():
prop.execute(selectcontext, instance, row, identitykey, isnew)
Mapper.logger = logging.class_logger(Mapper)
class MapperExtension(object):
"""base implementation for an object that provides overriding behavior to various
Mapper functions. For each method in MapperExtension, a result of EXT_PASS indicates
the functionality is not overridden."""
def get_session(self):
"""retrieve a contextual Session instance with which to register a new object.
Note: this is not called if a session is provided with the __init__ params (i.e. _sa_session)"""
return EXT_PASS
def load(self, query, *args, **kwargs):
"""override the load method of the Query object.
the return value of this method is used as the result of query.load() if the
value is anything other than EXT_PASS."""
return EXT_PASS
def get(self, query, *args, **kwargs):
"""override the get method of the Query object.
the return value of this method is used as the result of query.get() if the
value is anything other than EXT_PASS."""
return EXT_PASS
def get_by(self, query, *args, **kwargs):
"""override the get_by method of the Query object.
the return value of this method is used as the result of query.get_by() if the
value is anything other than EXT_PASS."""
return EXT_PASS
def select_by(self, query, *args, **kwargs):
"""override the select_by method of the Query object.
the return value of this method is used as the result of query.select_by() if the
value is anything other than EXT_PASS."""
return EXT_PASS
def select(self, query, *args, **kwargs):
"""override the select method of the Query object.
the return value of this method is used as the result of query.select() if the
value is anything other than EXT_PASS."""
return EXT_PASS
def create_instance(self, mapper, selectcontext, row, class_):
"""receieve a row when a new object instance is about to be created from that row.
the method can choose to create the instance itself, or it can return
None to indicate normal object creation should take place.
mapper - the mapper doing the operation
selectcontext - SelectionContext corresponding to the instances() call
row - the result row from the database
class_ - the class we are mapping.
"""
return EXT_PASS
def append_result(self, mapper, selectcontext, row, instance, identitykey, result, isnew):
"""receive an object instance before that instance is appended to a result list.
If this method returns EXT_PASS, result appending will proceed normally.
if this method returns any other value or None, result appending will not proceed for
this instance, giving this extension an opportunity to do the appending itself, if desired.
mapper - the mapper doing the operation
selectcontext - SelectionContext corresponding to the instances() call
row - the result row from the database
instance - the object instance to be appended to the result
identitykey - the identity key of the instance
result - list to which results are being appended
isnew - indicates if this is the first time we have seen this object instance in the current result
set. if you are selecting from a join, such as an eager load, you might see the same object instance
many times in the same result set.
"""
return EXT_PASS
def populate_instance(self, mapper, selectcontext, row, instance, identitykey, isnew):
"""receive a newly-created instance before that instance has its attributes populated.
The normal population of attributes is according to each
attribute's corresponding MapperProperty (which includes column-based attributes as well
as relationships to other classes). If this method returns EXT_PASS, instance population
will proceed normally. If any other value or None is returned, instance population
will not proceed, giving this extension an opportunity to populate the instance itself,
if desired.
"""
return EXT_PASS
def before_insert(self, mapper, connection, instance):
"""receive an object instance before that instance is INSERTed into its table.
this is a good place to set up primary key values and such that arent handled otherwise."""
return EXT_PASS
def before_update(self, mapper, connection, instance):
"""receive an object instance before that instance is UPDATEed."""
return EXT_PASS
def after_update(self, mapper, connection, instance):
"""receive an object instance after that instance is UPDATEed."""
return EXT_PASS
def after_insert(self, mapper, connection, instance):
"""receive an object instance after that instance is INSERTed."""
return EXT_PASS
def before_delete(self, mapper, connection, instance):
"""receive an object instance before that instance is DELETEed."""
return EXT_PASS
def after_delete(self, mapper, connection, instance):
"""receive an object instance after that instance is DELETEed."""
return EXT_PASS
class _ExtensionCarrier(MapperExtension):
def __init__(self):
self.__elements = []
self.__callables = {}
def insert(self, extension):
"""insert a MapperExtension at the beginning of this ExtensionCarrier's list."""
self.__elements.insert(0, extension)
def append(self, extension):
"""append a MapperExtension at the end of this ExtensionCarrier's list."""
self.__elements.append(extension)
def __getattribute__(self, key):
if key in MapperExtension.__dict__:
try:
return self.__callables[key]
except KeyError:
return self.__callables.setdefault(key, lambda *args, **kwargs:self._do(key, *args, **kwargs))
else:
return super(_ExtensionCarrier, self).__getattribute__(key)
def _do(self, funcname, *args, **kwargs):
for elem in self.__elements:
if elem is self:
raise exceptions.AssertionError("ExtensionCarrier set to itself")
ret = getattr(elem, funcname)(*args, **kwargs)
if ret is not EXT_PASS:
return ret
else:
return EXT_PASS
class ExtensionOption(MapperOption):
def __init__(self, ext):
self.ext = ext
def process_query(self, query):
query._insert_extension(self.ext)
class ClassKey(object):
"""keys a class and an entity name to a mapper, via the mapper_registry."""
__metaclass__ = util.ArgSingleton
def __init__(self, class_, entity_name):
self.class_ = class_
self.entity_name = entity_name
def __hash__(self):
return hash((self.class_, self.entity_name))
def __eq__(self, other):
return self is other
def __repr__(self):
return "ClassKey(%s, %s)" % (repr(self.class_), repr(self.entity_name))
def has_identity(object):
return hasattr(object, '_instance_key')
def has_mapper(object):
"""returns True if the given object has a mapper association"""
return hasattr(object, '_entity_name')
def object_mapper(object, raiseerror=True):
"""given an object, returns the primary Mapper associated with the object instance"""
try:
mapper = mapper_registry[ClassKey(object.__class__, getattr(object, '_entity_name', None))]
except (KeyError, AttributeError):
if raiseerror:
raise exceptions.InvalidRequestError("Class '%s' entity name '%s' has no mapper associated with it" % (object.__class__.__name__, getattr(object, '_entity_name', None)))
else:
return None
return mapper.compile()
def class_mapper(class_, entity_name=None, compile=True):
"""given a ClassKey, returns the primary Mapper associated with the key."""
try:
mapper = mapper_registry[ClassKey(class_, entity_name)]
except (KeyError, AttributeError):
raise exceptions.InvalidRequestError("Class '%s' entity name '%s' has no mapper associated with it" % (class_.__name__, entity_name))
if compile:
return mapper.compile()
else:
return mapper
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