# mapper.py # Copyright (C) 2005, 2006, 2007, 2008, 2009 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 """Logic to map Python classes to and from selectables. Defines the :class:`~sqlalchemy.orm.mapper.Mapper` class, the central configurational unit which associates a class with a database table. This is a semi-private module; the main configurational API of the ORM is available in :class:`~sqlalchemy.orm.`. """ import types import weakref import operator from itertools import chain deque = __import__('collections').deque from sqlalchemy import sql, util, log, exc as sa_exc from sqlalchemy.sql import expression, visitors, operators, util as sqlutil from sqlalchemy.orm import attributes, exc, sync from sqlalchemy.orm.interfaces import ( MapperProperty, EXT_CONTINUE, PropComparator ) from sqlalchemy.orm.util import ( ExtensionCarrier, _INSTRUMENTOR, _class_to_mapper, _state_has_identity, _state_mapper, class_mapper, instance_str, state_str, ) __all__ = ( 'Mapper', '_mapper_registry', 'class_mapper', 'object_mapper', ) _mapper_registry = weakref.WeakKeyDictionary() _new_mappers = False _already_compiling = False # 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 = util.symbol('NO_ATTRIBUTE') # lock used to synchronize the "mapper compile" step _COMPILE_MUTEX = util.threading.RLock() # initialize these lazily ColumnProperty = None SynonymProperty = None ComparableProperty = None RelationProperty = None ConcreteInheritedProperty = None _expire_state = None _state_session = None class Mapper(object): """Define the correlation of class attributes to database table columns. Instances of this class should be constructed via the :func:`~sqlalchemy.orm.mapper` function. """ def __init__(self, class_, local_table, properties = None, primary_key = None, non_primary = False, inherits = None, inherit_condition = None, inherit_foreign_keys = None, extension = None, order_by = False, always_refresh = False, version_id_col = None, polymorphic_on=None, _polymorphic_map=None, polymorphic_identity=None, polymorphic_fetch=None, concrete=False, select_table=None, with_polymorphic=None, allow_null_pks=False, batch=True, column_prefix=None, include_properties=None, exclude_properties=None, eager_defaults=False): """Construct a new mapper. Mappers are normally constructed via the :func:`~sqlalchemy.orm.mapper` function. See for details. """ self.class_ = util.assert_arg_type(class_, type, 'class_') self.class_manager = None self.primary_key_argument = primary_key self.non_primary = non_primary if order_by: self.order_by = util.to_list(order_by) else: 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.local_table = local_table self.inherit_condition = inherit_condition self.inherit_foreign_keys = inherit_foreign_keys self.extension = extension self._init_properties = properties or {} self.allow_null_pks = allow_null_pks self.delete_orphans = [] self.batch = batch self.eager_defaults = eager_defaults self.column_prefix = column_prefix self.polymorphic_on = polymorphic_on self._dependency_processors = [] self._validators = {} self._clause_adapter = None self._requires_row_aliasing = False self._inherits_equated_pairs = None self.select_table = select_table if select_table: util.warn_deprecated('select_table option is deprecated. Use with_polymorphic=("*", selectable) ' 'instead.') if with_polymorphic: raise sa_exc.ArgumentError("select_table can't be used with " "with_polymorphic (they define conflicting settings)") self.with_polymorphic = ('*', select_table) else: if with_polymorphic == '*': self.with_polymorphic = ('*', None) elif isinstance(with_polymorphic, (tuple, list)): if isinstance(with_polymorphic[0], (basestring, tuple, list)): self.with_polymorphic = with_polymorphic else: self.with_polymorphic = (with_polymorphic, None) elif with_polymorphic is not None: raise sa_exc.ArgumentError("Invalid setting for with_polymorphic") else: self.with_polymorphic = None if isinstance(self.local_table, expression._SelectBaseMixin): util.warn("mapper %s creating an alias for the given " "selectable. References to the original selectable " "may be misinterpreted by queries, polymorphic_on, etc. " " Consider passing an explicit selectable.alias() construct instead." % self) self.local_table = self.local_table.alias() if self.with_polymorphic and isinstance(self.with_polymorphic[1], expression._SelectBaseMixin): self.with_polymorphic = (self.with_polymorphic[0], self.with_polymorphic[1].alias()) # 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 if polymorphic_fetch: util.warn_deprecated('polymorphic_fetch option is deprecated. Unloaded columns ' 'load as deferred in all cases; loading can be controlled ' 'using the "with_polymorphic" option.') # 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 self.include_properties = include_properties self.exclude_properties = exclude_properties self.compiled = False self._configure_inheritance() self._configure_extensions() self._configure_class_instrumentation() self._configure_properties() self._configure_pks() global _new_mappers _new_mappers = True self._log("constructed") # configurational / mutating methods. not threadsafe # except for compile(). def _configure_inheritance(self): """Configure settings related to inherting and/or inherited mappers being present.""" # a set of all mappers which inherit from this one. self._inheriting_mappers = set() if self.inherits: if isinstance(self.inherits, type): self.inherits = class_mapper(self.inherits, compile=False) if not issubclass(self.class_, self.inherits.class_): raise sa_exc.ArgumentError( "Class '%s' does not inherit from '%s'" % (self.class_.__name__, self.inherits.class_.__name__)) if self.non_primary != self.inherits.non_primary: np = not self.non_primary and "primary" or "non-primary" raise sa_exc.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.mapped_table = self.inherits.mapped_table self.single = True elif not self.local_table is self.inherits.local_table: if self.concrete: self.mapped_table = self.local_table for mapper in self.iterate_to_root(): if mapper.polymorphic_on: mapper._requires_row_aliasing = True else: if not self.inherit_condition: # 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 = sqlutil.join_condition(self.inherits.local_table, self.local_table) self.mapped_table = sql.join(self.inherits.mapped_table, self.local_table, self.inherit_condition) fks = util.to_set(self.inherit_foreign_keys) self._inherits_equated_pairs = sqlutil.criterion_as_pairs(self.mapped_table.onclause, consider_as_foreign_keys=fks) else: self.mapped_table = self.local_table if self.polymorphic_identity and not self.concrete: self._identity_class = self.inherits._identity_class else: self._identity_class = self.class_ if self.version_id_col is None: self.version_id_col = self.inherits.version_id_col for mapper in self.iterate_to_root(): util.reset_memoized(mapper, '_equivalent_columns') util.reset_memoized(mapper, '_sorted_tables') if self.order_by is False and not self.concrete and self.inherits.order_by is not 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) self.base_mapper = self.inherits.base_mapper self._all_tables = self.inherits._all_tables if self.polymorphic_identity is not None: self.polymorphic_map[self.polymorphic_identity] = self if not self.polymorphic_on: for mapper in self.iterate_to_root(): # try to set up polymorphic on using correesponding_column(); else leave # as None if mapper.polymorphic_on: self.polymorphic_on = self.mapped_table.corresponding_column(mapper.polymorphic_on) break else: self._all_tables = set() self.base_mapper = self self.mapped_table = self.local_table if self.polymorphic_identity: self.polymorphic_map[self.polymorphic_identity] = self self._identity_class = self.class_ if self.mapped_table is None: raise sa_exc.ArgumentError("Mapper '%s' does not have a mapped_table specified." % self) def _configure_extensions(self): """Go 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.OrderedSet() extension = self.extension if extension: for ext_obj in util.to_list(extension): # local MapperExtensions have already instrumented the class extlist.add(ext_obj) if self.inherits: for ext in self.inherits.extension: if ext not in extlist: extlist.add(ext) else: for ext in global_extensions: if isinstance(ext, type): ext = ext() if ext not in extlist: extlist.add(ext) self.extension = ExtensionCarrier() for ext in extlist: self.extension.append(ext) def _configure_class_instrumentation(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 decorate the `__init__` method on the mapped class to include optional auto-session attachment logic. """ manager = attributes.manager_of_class(self.class_) if self.non_primary: if not manager or manager.mapper is None: raise sa_exc.InvalidRequestError( "Class %s has no primary mapper configured. Configure " "a primary mapper first before setting up a non primary " "Mapper.") self.class_manager = manager _mapper_registry[self] = True return if manager is not None: assert manager.class_ is self.class_ if manager.mapper: raise sa_exc.ArgumentError( "Class '%s' already has a primary mapper defined. " "Use non_primary=True to " "create a non primary Mapper. clear_mappers() will " "remove *all* current mappers from all classes." % self.class_) #else: # a ClassManager may already exist as # ClassManager.instrument_attribute() creates # new managers for each subclass if they don't yet exist. _mapper_registry[self] = True self.extension.instrument_class(self, self.class_) if manager is None: manager = attributes.register_class(self.class_, deferred_scalar_loader = _load_scalar_attributes ) self.class_manager = manager manager.mapper = self # The remaining members can be added by any mapper, e_name None or not. if manager.info.get(_INSTRUMENTOR, False): return event_registry = manager.events event_registry.add_listener('on_init', _event_on_init) event_registry.add_listener('on_init_failure', _event_on_init_failure) event_registry.add_listener('on_resurrect', _event_on_resurrect) for key, method in util.iterate_attributes(self.class_): if isinstance(method, types.FunctionType): if hasattr(method, '__sa_reconstructor__'): event_registry.add_listener('on_load', method) elif hasattr(method, '__sa_validators__'): for name in method.__sa_validators__: self._validators[name] = method if 'reconstruct_instance' in self.extension: def reconstruct(instance): self.extension.reconstruct_instance(self, instance) event_registry.add_listener('on_load', reconstruct) manager.info[_INSTRUMENTOR] = self def dispose(self): # Disable any attribute-based compilation. self.compiled = True if hasattr(self, '_compile_failed'): del self._compile_failed if not self.non_primary and self.class_manager.mapper is self: attributes.unregister_class(self.class_) def _configure_pks(self): self.tables = sqlutil.find_tables(self.mapped_table) if not self.tables: raise sa_exc.InvalidRequestError("Could not find any Table objects in mapped table '%s'" % str(self.mapped_table)) self._pks_by_table = {} self._cols_by_table = {} all_cols = util.column_set(chain(*[col.proxy_set for col in self._columntoproperty])) pk_cols = util.column_set(c for c in all_cols if c.primary_key) # identify primary key columns which are also mapped by this mapper. tables = set(self.tables + [self.mapped_table]) self._all_tables.update(tables) for t in tables: if t.primary_key and pk_cols.issuperset(t.primary_key): # ordering is important since it determines the ordering of mapper.primary_key (and therefore query.get()) self._pks_by_table[t] = util.ordered_column_set(t.primary_key).intersection(pk_cols) self._cols_by_table[t] = util.ordered_column_set(t.c).intersection(all_cols) # determine cols that aren't expressed within our tables; mark these # as "read only" properties which are refreshed upon INSERT/UPDATE self._readonly_props = set( self._columntoproperty[col] for col in self._columntoproperty if not hasattr(col, 'table') or col.table not in self._cols_by_table) # if explicit PK argument sent, add those columns to the primary key mappings if self.primary_key_argument: for k in self.primary_key_argument: if k.table not in self._pks_by_table: self._pks_by_table[k.table] = util.OrderedSet() self._pks_by_table[k.table].add(k) if self.mapped_table not in self._pks_by_table or len(self._pks_by_table[self.mapped_table]) == 0: raise sa_exc.ArgumentError("Mapper %s could not assemble any primary " "key columns for mapped table '%s'" % (self, self.mapped_table.description)) if self.inherits and not self.concrete and not self.primary_key_argument: # if inheriting, the "primary key" for this mapper is that of the inheriting (unless concrete or explicit) self.primary_key = self.inherits.primary_key else: # determine primary key from argument or mapped_table pks - reduce to the minimal set of columns if self.primary_key_argument: primary_key = sqlutil.reduce_columns( [self.mapped_table.corresponding_column(c) for c in self.primary_key_argument], ignore_nonexistent_tables=True) else: primary_key = sqlutil.reduce_columns( self._pks_by_table[self.mapped_table], ignore_nonexistent_tables=True) if len(primary_key) == 0: raise sa_exc.ArgumentError("Mapper %s could not assemble any primary " "key columns for mapped table '%s'" % (self, self.mapped_table.description)) self.primary_key = primary_key self._log("Identified primary key columns: " + str(primary_key)) def _configure_properties(self): # Column and other ClauseElement objects which are mapped self.columns = self.c = util.OrderedProperties() # object attribute names mapped to MapperProperty objects self._props = util.OrderedDict() # 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 = util.column_dict() # load custom properties if self._init_properties: for key, prop in self._init_properties.iteritems(): self._configure_property(key, prop, False) # pull properties from the inherited mapper if any. if self.inherits: for key, prop in self.inherits._props.iteritems(): if key not in self._props and not self._should_exclude(key, key, local=False): self._adapt_inherited_property(key, prop, False) # create properties for each column in the mapped table, # for those columns which don't already map to a property for column in self.mapped_table.columns: if column in self._columntoproperty: continue column_key = (self.column_prefix or '') + column.key if self._should_exclude(column.key, column_key, local=self.local_table.c.contains_column(column)): continue # adjust the "key" used for this column to that # of the inheriting mapper for mapper in self.iterate_to_root(): if column in mapper._columntoproperty: column_key = mapper._columntoproperty[column].key self._configure_property(column_key, column, init=False, setparent=True) # do a special check for the "discriminiator" column, as it may only be present # in the 'with_polymorphic' selectable but we need it for the base mapper if self.polymorphic_on and self.polymorphic_on not in self._columntoproperty: col = self.mapped_table.corresponding_column(self.polymorphic_on) if not col: dont_instrument = True col = self.polymorphic_on else: dont_instrument = False if self._should_exclude(col.key, col.key, local=False): raise sa_exc.InvalidRequestError("Cannot exclude or override the discriminator column %r" % col.key) self._configure_property(col.key, ColumnProperty(col, _no_instrument=dont_instrument), init=False, setparent=True) def _adapt_inherited_property(self, key, prop, init): if not self.concrete: self._configure_property(key, prop, init=False, setparent=False) elif key not in self._props: self._configure_property(key, ConcreteInheritedProperty(), init=init, setparent=True) def _configure_property(self, key, prop, init=True, setparent=True): self._log("_configure_property(%s, %s)" % (key, prop.__class__.__name__)) if not isinstance(prop, MapperProperty): # we were passed a Column or a list of Columns; generate a ColumnProperty columns = util.to_list(prop) column = columns[0] if not expression.is_column(column): raise sa_exc.ArgumentError("%s=%r is not an instance of MapperProperty or Column" % (key, prop)) prop = self._props.get(key, None) if isinstance(prop, ColumnProperty): # TODO: the "property already exists" case is still not well defined here. # assuming single-column, etc. if prop.parent is not self: # existing ColumnProperty from an inheriting mapper. # make a copy and append our column to it prop = prop.copy() prop.columns.append(column) self._log("appending to existing ColumnProperty %s" % (key)) elif prop is None or isinstance(prop, ConcreteInheritedProperty): mapped_column = [] for c in columns: mc = self.mapped_table.corresponding_column(c) if not mc: raise sa_exc.ArgumentError("Column '%s' is not represented in mapper's table. " "Use the `column_property()` function to force this column " "to be mapped as a read-only attribute." % c) mapped_column.append(mc) prop = ColumnProperty(*mapped_column) else: raise sa_exc.ArgumentError("WARNING: column '%s' conflicts with property '%r'. " "To resolve this, map the column to the class under a different " "name in the 'properties' dictionary. Or, to remove all awareness " "of the column entirely (including its availability as a foreign key), " "use the 'include_properties' or 'exclude_properties' mapper arguments " "to control specifically which table columns get mapped." % (column.key, prop)) if isinstance(prop, ColumnProperty): col = self.mapped_table.corresponding_column(prop.columns[0]) # col might not be present! the selectable given to the mapper need not include "deferred" # columns (included in zblog tests) if col is None: col = prop.columns[0] # column is coming in after _readonly_props was initialized; check # for 'readonly' if hasattr(self, '_readonly_props') and \ (not hasattr(col, 'table') or col.table not in self._cols_by_table): self._readonly_props.add(prop) else: # if column is coming in after _cols_by_table was initialized, ensure the col is in the # right set if hasattr(self, '_cols_by_table') and col.table in self._cols_by_table and col not in self._cols_by_table[col.table]: self._cols_by_table[col.table].add(col) # if this ColumnProperty represents the "polymorphic discriminator" # column, mark it. We'll need this when rendering columns # in SELECT statements. if not hasattr(prop, '_is_polymorphic_discriminator'): prop._is_polymorphic_discriminator = (col is self.polymorphic_on or prop.columns[0] is self.polymorphic_on) self.columns[key] = col for col in prop.columns: for col in col.proxy_set: self._columntoproperty[col] = prop elif isinstance(prop, (ComparableProperty, SynonymProperty)) and setparent: if prop.descriptor is None: desc = getattr(self.class_, key, None) if self._is_userland_descriptor(desc): prop.descriptor = desc if getattr(prop, 'map_column', False): if key not in self.mapped_table.c: raise sa_exc.ArgumentError( "Can't compile synonym '%s': no column on table '%s' named '%s'" % (prop.name, self.mapped_table.description, key)) self._configure_property(prop.name, ColumnProperty(self.mapped_table.c[key]), init=init, setparent=setparent) self._props[key] = prop prop.key = key if setparent: prop.set_parent(self) if not self.non_primary: prop.instrument_class(self) for mapper in self._inheriting_mappers: mapper._adapt_inherited_property(key, prop, init) if init: prop.init() prop.post_instrument_class(self) def compile(self): """Compile this mapper and all other non-compiled mappers. This method checks the local compiled status as well as for any new mappers that have been defined, and is safe to call repeatedly. """ global _new_mappers if self.compiled and not _new_mappers: return self _COMPILE_MUTEX.acquire() try: try: global _already_compiling if _already_compiling: # re-entrance to compile() occurs rarely, when a class-mapped construct is # used within a ForeignKey, something that is possible # when using the declarative layer self._post_configure_properties() return _already_compiling = True try: # double-check inside mutex if self.compiled and not _new_mappers: return self # initialize properties on all mappers for mapper in list(_mapper_registry): if getattr(mapper, '_compile_failed', False): raise sa_exc.InvalidRequestError("One or more mappers failed to compile. Exception was probably " "suppressed within a hasattr() call. " "Message was: %s" % mapper._compile_failed) if not mapper.compiled: mapper._post_configure_properties() _new_mappers = False return self finally: _already_compiling = False except: import sys exc = sys.exc_info()[1] self._compile_failed = exc raise finally: _COMPILE_MUTEX.release() def _post_configure_properties(self): """Call the ``init()`` method on all ``MapperProperties`` attached to this mapper. This is a deferred configuration step which is intended to execute once all mappers have been constructed. """ self._log("_post_configure_properties() started") l = [(key, prop) for key, prop in self._props.iteritems()] for key, prop in l: self._log("initialize prop " + key) if prop.parent is self and not prop._compile_started: prop.init() if prop._compile_finished: prop.post_instrument_class(self) self._log("_post_configure_properties() complete") self.compiled = True def add_properties(self, dict_of_properties): """Add 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 individual 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._init_properties[key] = prop self._configure_property(key, prop, init=self.compiled) # class formatting / logging. def _log(self, msg): if self._should_log_info: self.logger.info( "(" + self.class_.__name__ + "|" + (self.local_table and self.local_table.description or str(self.local_table)) + (self.non_primary and "|non-primary" or "") + ") " + msg) def _log_debug(self, msg): if self._should_log_debug: self.logger.debug( "(" + self.class_.__name__ + "|" + (self.local_table and self.local_table.description or str(self.local_table)) + (self.non_primary and "|non-primary" or "") + ") " + msg) def __repr__(self): return '' % ( id(self), self.class_.__name__) def __str__(self): return "Mapper|" + self.class_.__name__ + "|" + \ (self.local_table and self.local_table.description or str(self.local_table)) + \ (self.non_primary and "|non-primary" or "") # informational / status def _is_orphan(self, state): o = False for mapper in self.iterate_to_root(): for (key, cls) in mapper.delete_orphans: if attributes.manager_of_class(cls).has_parent( state, key, optimistic=_state_has_identity(state)): return False o = o or bool(mapper.delete_orphans) return o def has_property(self, key): return key in self._props def get_property(self, key, resolve_synonyms=False, raiseerr=True): """return a MapperProperty associated with the given key.""" self.compile() return self._get_property(key, resolve_synonyms=resolve_synonyms, raiseerr=raiseerr) def _get_property(self, key, resolve_synonyms=False, raiseerr=True): prop = self._props.get(key, None) if resolve_synonyms: while isinstance(prop, SynonymProperty): prop = self._props.get(prop.name, None) if prop is None and raiseerr: raise sa_exc.InvalidRequestError("Mapper '%s' has no property '%s'" % (str(self), key)) return prop @property def iterate_properties(self): """return an iterator of all MapperProperty objects.""" self.compile() return self._props.itervalues() def _mappers_from_spec(self, spec, selectable): """given a with_polymorphic() argument, return the set of mappers it represents. Trims the list of mappers to just those represented within the given selectable, if present. This helps some more legacy-ish mappings. """ if spec == '*': mappers = list(self.polymorphic_iterator()) elif spec: mappers = [_class_to_mapper(m) for m in util.to_list(spec)] for m in mappers: if not m.isa(self): raise sa_exc.InvalidRequestError("%r does not inherit from %r" % (m, self)) else: mappers = [] if selectable: tables = set(sqlutil.find_tables(selectable, include_aliases=True)) mappers = [m for m in mappers if m.local_table in tables] return mappers def _selectable_from_mappers(self, mappers): """given a list of mappers (assumed to be within this mapper's inheritance hierarchy), construct an outerjoin amongst those mapper's mapped tables. """ from_obj = self.mapped_table for m in mappers: if m is self: continue if m.concrete: raise sa_exc.InvalidRequestError("'with_polymorphic()' requires 'selectable' argument when concrete-inheriting mappers are used.") elif not m.single: from_obj = from_obj.outerjoin(m.local_table, m.inherit_condition) return from_obj @property def _single_table_criterion(self): if self.single and \ self.inherits and \ self.polymorphic_on and \ self.polymorphic_identity is not None: return self.polymorphic_on.in_( m.polymorphic_identity for m in self.polymorphic_iterator()) else: return None @util.memoized_property def _with_polymorphic_mappers(self): if not self.with_polymorphic: return [self] return self._mappers_from_spec(*self.with_polymorphic) @util.memoized_property def _with_polymorphic_selectable(self): if not self.with_polymorphic: return self.mapped_table spec, selectable = self.with_polymorphic if selectable: return selectable else: return self._selectable_from_mappers(self._mappers_from_spec(spec, selectable)) def _with_polymorphic_args(self, spec=None, selectable=False): if self.with_polymorphic: if not spec: spec = self.with_polymorphic[0] if selectable is False: selectable = self.with_polymorphic[1] mappers = self._mappers_from_spec(spec, selectable) if selectable: return mappers, selectable else: return mappers, self._selectable_from_mappers(mappers) def _iterate_polymorphic_properties(self, mappers=None): """Return an iterator of MapperProperty objects which will render into a SELECT.""" if mappers is None: mappers = self._with_polymorphic_mappers if not mappers: for c in self.iterate_properties: yield c else: # in the polymorphic case, filter out discriminator columns # from other mappers, as these are sometimes dependent on that # mapper's polymorphic selectable (which we don't want rendered) for c in util.unique_list( chain(*[list(mapper.iterate_properties) for mapper in [self] + mappers]) ): if getattr(c, '_is_polymorphic_discriminator', False) and \ (not self.polymorphic_on or c.columns[0] is not self.polymorphic_on): continue yield c @property def properties(self): raise NotImplementedError("Public collection of MapperProperty objects is " "provided by the get_property() and iterate_properties accessors.") @util.memoized_property def _get_clause(self): """create a "get clause" based on the primary key. this is used by query.get() and many-to-one lazyloads to load this item by primary key. """ params = [(primary_key, sql.bindparam(None, type_=primary_key.type)) for primary_key in self.primary_key] return sql.and_(*[k==v for (k, v) in params]), util.column_dict(params) @util.memoized_property def _equivalent_columns(self): """Create a map of all *equivalent* columns, based on the determination of column pairs that are equated to one another based on inherit condition. This is designed to work with the queries that util.polymorphic_union comes up with, which often don't include the columns from the base table directly (including the subclass table columns only). The resulting structure is a dictionary of columns mapped to lists of equivalent columns, i.e. { tablea.col1: set([tableb.col1, tablec.col1]), tablea.col2: set([tabled.col2]) } """ result = util.column_dict() def visit_binary(binary): if binary.operator == operators.eq: if binary.left in result: result[binary.left].add(binary.right) else: result[binary.left] = util.column_set((binary.right,)) if binary.right in result: result[binary.right].add(binary.left) else: result[binary.right] = util.column_set((binary.left,)) for mapper in self.base_mapper.polymorphic_iterator(): if mapper.inherit_condition: visitors.traverse(mapper.inherit_condition, {}, {'binary':visit_binary}) return result def _is_userland_descriptor(self, obj): return not isinstance(obj, (MapperProperty, attributes.InstrumentedAttribute)) and hasattr(obj, '__get__') def _should_exclude(self, name, assigned_name, local): """determine whether a particular property should be implicitly present on the class. This occurs when properties are propagated from an inherited class, or are applied from the columns present in the mapped table. """ # check for descriptors, either local or from # an inherited class if local: if self.class_.__dict__.get(assigned_name, None)\ and self._is_userland_descriptor(self.class_.__dict__[assigned_name]): return True else: if getattr(self.class_, assigned_name, None)\ and self._is_userland_descriptor(getattr(self.class_, assigned_name)): return True if (self.include_properties is not None and name not in self.include_properties): self._log("not including property %s" % (name)) return True if (self.exclude_properties is not None and name in self.exclude_properties): self._log("excluding property %s" % (name)) return True return False 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 _canload(self, state, allow_subtypes): s = self.primary_mapper() if self.polymorphic_on or allow_subtypes: return _state_mapper(state).isa(s) else: return _state_mapper(state) is s def isa(self, other): """Return True if the this mapper inherits from the given mapper.""" m = self while m and m is not other: m = m.inherits return bool(m) def iterate_to_root(self): m = self while m: yield m m = m.inherits def polymorphic_iterator(self): """Iterate 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()``. """ stack = deque([self]) while stack: item = stack.popleft() yield item stack.extend(item._inheriting_mappers) def primary_mapper(self): """Return the primary mapper corresponding to this mapper's class key (class).""" return self.class_manager.mapper def identity_key_from_row(self, row, adapter=None): """Return an identity-map key for use in storing/retrieving an item from the identity map. row A ``sqlalchemy.engine.base.RowProxy`` instance or a dictionary corresponding result-set ``ColumnElement`` instances to their values within a row. """ pk_cols = self.primary_key if adapter: pk_cols = [adapter.columns[c] for c in pk_cols] return (self._identity_class, tuple(row[column] for column in pk_cols)) 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._identity_class, tuple(util.to_list(primary_key))) 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 state under the attribute name `key`. """ return self.identity_key_from_primary_key(self.primary_key_from_instance(instance)) def _identity_key_from_state(self, state): return self.identity_key_from_primary_key(self._primary_key_from_state(state)) def primary_key_from_instance(self, instance): """Return the list of primary key values for the given instance. """ state = attributes.instance_state(instance) return self._primary_key_from_state(state) def _primary_key_from_state(self, state): return [self._get_state_attr_by_column(state, column) for column in self.primary_key] def _get_col_to_prop(self, column): try: return self._columntoproperty[column] except KeyError: prop = self._props.get(column.key, None) if prop: raise exc.UnmappedColumnError("Column '%s.%s' is not available, due to conflicting property '%s':%s" % (column.table.name, column.name, column.key, repr(prop))) else: raise exc.UnmappedColumnError("No column %s is configured on mapper %s..." % (column, self)) # TODO: improve names? def _get_state_attr_by_column(self, state, column): return self._get_col_to_prop(column).getattr(state, column) def _set_state_attr_by_column(self, state, column, value): return self._get_col_to_prop(column).setattr(state, value, column) def _get_committed_attr_by_column(self, obj, column): state = attributes.instance_state(obj) return self._get_committed_state_attr_by_column(state, column) def _get_committed_state_attr_by_column(self, state, column, passive=False): return self._get_col_to_prop(column).getcommitted(state, column, passive=passive) def _optimized_get_statement(self, state, attribute_names): """assemble a WHERE clause which retrieves a given state by primary key, using a minimized set of tables. Applies to a joined-table inheritance mapper where the requested attribute names are only present on joined tables, not the base table. The WHERE clause attempts to include only those tables to minimize joins. """ props = self._props tables = set(props[key].parent.local_table for key in attribute_names) if self.base_mapper.local_table in tables: return None class ColumnsNotAvailable(Exception): pass def visit_binary(binary): leftcol = binary.left rightcol = binary.right if leftcol is None or rightcol is None: return if leftcol.table not in tables: leftval = self._get_committed_state_attr_by_column(state, leftcol, passive=True) if leftval is attributes.PASSIVE_NORESULT: raise ColumnsNotAvailable() binary.left = sql.bindparam(None, leftval, type_=binary.right.type) elif rightcol.table not in tables: rightval = self._get_committed_state_attr_by_column(state, rightcol, passive=True) if rightval is attributes.PASSIVE_NORESULT: raise ColumnsNotAvailable() binary.right = sql.bindparam(None, rightval, type_=binary.right.type) allconds = [] try: start = False for mapper in reversed(list(self.iterate_to_root())): if mapper.local_table in tables: start = True if start and not mapper.single: allconds.append(visitors.cloned_traverse(mapper.inherit_condition, {}, {'binary':visit_binary})) except ColumnsNotAvailable: return None cond = sql.and_(*allconds) return sql.select(tables, cond, use_labels=True) def cascade_iterator(self, type_, state, halt_on=None): """Iterate each element and its mapper 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.) ``state``: The lead InstanceState. child items will be processed per the relations defined for this object's mapper. the return value are object instances; this provides a strong reference so that they don't fall out of scope immediately. """ visited_instances = util.IdentitySet() visitables = [(self._props.itervalues(), 'property', state)] while visitables: iterator, item_type, parent_state = visitables[-1] try: if item_type == 'property': prop = iterator.next() visitables.append((prop.cascade_iterator(type_, parent_state, visited_instances, halt_on), 'mapper', None)) elif item_type == 'mapper': instance, instance_mapper, corresponding_state = iterator.next() yield (instance, instance_mapper) visitables.append((instance_mapper._props.itervalues(), 'property', corresponding_state)) except StopIteration: visitables.pop() # persistence @util.memoized_property def _sorted_tables(self): table_to_mapper = {} for mapper in self.base_mapper.polymorphic_iterator(): for t in mapper.tables: table_to_mapper[t] = mapper sorted_ = sqlutil.sort_tables(table_to_mapper.iterkeys()) ret = util.OrderedDict() for t in sorted_: ret[t] = table_to_mapper[t] return ret def _save_obj(self, states, 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. """ if self._should_log_debug: 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 state in _sort_states(states): self._save_obj([state], uowtransaction, postupdate=postupdate, post_update_cols=post_update_cols, single=True) return # if session has a connection callable, # organize individual states with the connection to use for insert/update tups = [] if 'connection_callable' in uowtransaction.mapper_flush_opts: connection_callable = uowtransaction.mapper_flush_opts['connection_callable'] for state in _sort_states(states): m = _state_mapper(state) tups.append( ( state, m, connection_callable(self, state.obj()), _state_has_identity(state), state.key or m._identity_key_from_state(state) ) ) else: connection = uowtransaction.transaction.connection(self) for state in _sort_states(states): m = _state_mapper(state) tups.append( ( state, m, connection, _state_has_identity(state), state.key or m._identity_key_from_state(state) ) ) if not postupdate: # call before_XXX extensions for state, mapper, connection, has_identity, instance_key in tups: if not has_identity: if 'before_insert' in mapper.extension: mapper.extension.before_insert(mapper, connection, state.obj()) else: if 'before_update' in mapper.extension: mapper.extension.before_update(mapper, connection, state.obj()) row_switches = set() if not postupdate: for state, mapper, connection, has_identity, instance_key in tups: # 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. if not has_identity and instance_key in uowtransaction.session.identity_map: instance = uowtransaction.session.identity_map[instance_key] existing = attributes.instance_state(instance) if not uowtransaction.is_deleted(existing): raise exc.FlushError( "New instance %s with identity key %s conflicts with persistent instance %s" % (state_str(state), instance_key, state_str(existing))) if self._should_log_debug: self._log_debug( "detected row switch for identity %s. will update %s, remove %s from transaction", instance_key, state_str(state), state_str(existing)) # remove the "delete" flag from the existing element uowtransaction.set_row_switch(existing) row_switches.add(state) table_to_mapper = self._sorted_tables for table in table_to_mapper.iterkeys(): insert = [] update = [] for state, mapper, connection, has_identity, instance_key in tups: if table not in mapper._pks_by_table: continue pks = mapper._pks_by_table[table] if self._should_log_debug: self._log_debug("_save_obj() table '%s' instance %s identity %s" % (table.name, state_str(state), str(instance_key))) isinsert = not has_identity and not postupdate and state not in row_switches params = {} value_params = {} hasdata = False if isinsert: for col in mapper._cols_by_table[table]: if col is mapper.version_id_col: params[col.key] = 1 elif mapper.polymorphic_on and mapper.polymorphic_on.shares_lineage(col): if self._should_log_debug: 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 and col.server_default is None) or value is not None): params[col.key] = value elif col in pks: value = mapper._get_state_attr_by_column(state, col) if value is not None: params[col.key] = value else: value = mapper._get_state_attr_by_column(state, col) if ((col.default is None and col.server_default is None) or value is not None): if isinstance(value, sql.ClauseElement): value_params[col] = value else: params[col.key] = value insert.append((state, params, mapper, connection, value_params)) else: for col in mapper._cols_by_table[table]: if col is mapper.version_id_col: params[col._label] = mapper._get_state_attr_by_column(state, col) params[col.key] = params[col._label] + 1 for prop in mapper._columntoproperty.itervalues(): history = attributes.get_state_history(state, prop.key, passive=True) if history.added: hasdata = True elif mapper.polymorphic_on and mapper.polymorphic_on.shares_lineage(col): pass else: if post_update_cols is not None and col not in post_update_cols: if col in pks: params[col._label] = mapper._get_state_attr_by_column(state, col) continue prop = mapper._columntoproperty[col] history = attributes.get_state_history(state, prop.key, passive=True) if history.added: if isinstance(history.added[0], sql.ClauseElement): value_params[col] = history.added[0] else: params[col.key] = prop.get_col_value(col, history.added[0]) if col in pks: if history.deleted: params[col._label] = prop.get_col_value(col, history.deleted[0]) hasdata = True else: # row switch logic can reach us here # remove the pk from the update params so the update doesn't # attempt to include the pk in the update statement del params[col.key] params[col._label] = prop.get_col_value(col, history.added[0]) else: hasdata = True elif col in pks: params[col._label] = mapper._get_state_attr_by_column(state, col) if hasdata: update.append((state, params, mapper, connection, value_params)) if 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 and table.c.contains_column(mapper.version_id_col): clause.clauses.append(mapper.version_id_col == sql.bindparam(mapper.version_id_col._label, type_=col.type)) statement = table.update(clause) rows = 0 for state, params, mapper, connection, value_params in update: c = connection.execute(statement.values(value_params), params) mapper._postfetch(uowtransaction, connection, table, state, c, c.last_updated_params(), value_params) rows += c.rowcount if c.supports_sane_rowcount() and rows != len(update): raise exc.ConcurrentModificationError("Updated rowcount %d does not match number of objects updated %d" % (rows, len(update))) if insert: statement = table.insert() for state, params, mapper, connection, value_params in insert: c = connection.execute(statement.values(value_params), params) primary_key = c.last_inserted_ids() if primary_key is not None: # set primary key attributes for i, col in enumerate(mapper._pks_by_table[table]): if mapper._get_state_attr_by_column(state, col) is None and len(primary_key) > i: mapper._set_state_attr_by_column(state, col, primary_key[i]) mapper._postfetch(uowtransaction, connection, table, state, c, c.last_inserted_params(), value_params) # synchronize newly inserted ids from one table to the next # TODO: this performs some unnecessary attribute transfers # from an attribute to itself, since the attribute is often mapped # to multiple, equivalent columns. it also may fire off more # than needed overall. for m in mapper.iterate_to_root(): if m._inherits_equated_pairs: sync.populate(state, m, state, m, m._inherits_equated_pairs) if not postupdate: for state, mapper, connection, has_identity, instance_key in tups: # expire readonly attributes readonly = state.unmodified.intersection( p.key for p in mapper._readonly_props ) if readonly: _expire_state(state, readonly) # if specified, eagerly refresh whatever has # been expired. if self.eager_defaults and state.unloaded: state.key = self._identity_key_from_state(state) uowtransaction.session.query(self)._get( state.key, refresh_state=state, only_load_props=state.unloaded) # call after_XXX extensions if not has_identity: if 'after_insert' in mapper.extension: mapper.extension.after_insert(mapper, connection, state.obj()) else: if 'after_update' in mapper.extension: mapper.extension.after_update(mapper, connection, state.obj()) def _postfetch(self, uowtransaction, connection, table, state, resultproxy, params, value_params): """Expire attributes in need of newly persisted database state.""" postfetch_cols = resultproxy.postfetch_cols() generated_cols = list(resultproxy.prefetch_cols()) if self.polymorphic_on: po = table.corresponding_column(self.polymorphic_on) if po: generated_cols.append(po) if self.version_id_col: generated_cols.append(self.version_id_col) for c in generated_cols: if c.key in params and c in self._columntoproperty: self._set_state_attr_by_column(state, c, params[c.key]) deferred_props = [prop.key for prop in [self._columntoproperty[c] for c in postfetch_cols]] if deferred_props: _expire_state(state, deferred_props) def _delete_obj(self, states, uowtransaction): """Issue ``DELETE`` statements for a list of objects. This is called within the context of a UOWTransaction during a flush operation. """ if self._should_log_debug: self._log_debug("_delete_obj() start") if 'connection_callable' in uowtransaction.mapper_flush_opts: connection_callable = uowtransaction.mapper_flush_opts['connection_callable'] tups = [(state, _state_mapper(state), connection_callable(self, state.obj())) for state in _sort_states(states)] else: connection = uowtransaction.transaction.connection(self) tups = [(state, _state_mapper(state), connection) for state in _sort_states(states)] for state, mapper, connection in tups: if 'before_delete' in mapper.extension: mapper.extension.before_delete(mapper, connection, state.obj()) table_to_mapper = self._sorted_tables for table in reversed(table_to_mapper.keys()): delete = {} for state, mapper, connection in tups: if table not in mapper._pks_by_table: continue params = {} if not _state_has_identity(state): continue else: delete.setdefault(connection, []).append(params) for col in mapper._pks_by_table[table]: params[col.key] = mapper._get_state_attr_by_column(state, col) if mapper.version_id_col and table.c.contains_column(mapper.version_id_col): params[mapper.version_id_col.key] = mapper._get_state_attr_by_column(state, mapper.version_id_col) for connection, del_objects in delete.iteritems(): mapper = table_to_mapper[table] clause = sql.and_() for col in mapper._pks_by_table[table]: clause.clauses.append(col == sql.bindparam(col.key, type_=col.type)) if mapper.version_id_col and table.c.contains_column(mapper.version_id_col): clause.clauses.append( mapper.version_id_col == sql.bindparam(mapper.version_id_col.key, type_=mapper.version_id_col.type)) statement = table.delete(clause) c = connection.execute(statement, del_objects) if c.supports_sane_multi_rowcount() and c.rowcount != len(del_objects): raise exc.ConcurrentModificationError("Deleted rowcount %d does not match " "number of objects deleted %d" % (c.rowcount, len(del_objects))) for state, mapper, connection in tups: if 'after_delete' in mapper.extension: mapper.extension.after_delete(mapper, connection, state.obj()) def _register_dependencies(self, uowcommit): """Register ``DependencyProcessor`` instances with a ``unitofwork.UOWTransaction``. This call `register_dependencies` on all attached ``MapperProperty`` instances. """ for dep in self._props.values() + self._dependency_processors: dep.register_dependencies(uowcommit) def _register_processors(self, uowcommit): for dep in self._props.values() + self._dependency_processors: dep.register_processors(uowcommit) # result set conversion def _instance_processor(self, context, path, adapter, polymorphic_from=None, extension=None, only_load_props=None, refresh_state=None, polymorphic_discriminator=None): """Produce a mapper level row processor callable which processes rows into mapped instances.""" pk_cols = self.primary_key if polymorphic_from or refresh_state: polymorphic_on = None else: polymorphic_on = polymorphic_discriminator or self.polymorphic_on polymorphic_instances = util.PopulateDict(self._configure_subclass_mapper(context, path, adapter)) version_id_col = self.version_id_col if adapter: pk_cols = [adapter.columns[c] for c in pk_cols] if polymorphic_on: polymorphic_on = adapter.columns[polymorphic_on] if version_id_col: version_id_col = adapter.columns[version_id_col] identity_class = self._identity_class def identity_key(row): return (identity_class, tuple(row[column] for column in pk_cols)) new_populators = [] existing_populators = [] def populate_state(state, dict_, row, isnew, only_load_props, **flags): if isnew: if context.options: state.load_options = context.options if state.load_options: state.load_path = context.query._current_path + path if not new_populators: new_populators[:], existing_populators[:] = self._populators(context, path, row, adapter) if isnew: populators = new_populators else: populators = existing_populators if only_load_props: populators = [p for p in populators if p[0] in only_load_props] for key, populator in populators: populator(state, dict_, row, isnew=isnew, **flags) session_identity_map = context.session.identity_map if not extension: extension = self.extension translate_row = extension.get('translate_row', None) create_instance = extension.get('create_instance', None) populate_instance = extension.get('populate_instance', None) append_result = extension.get('append_result', None) populate_existing = context.populate_existing or self.always_refresh def _instance(row, result): if translate_row: ret = translate_row(self, context, row) if ret is not EXT_CONTINUE: row = ret if polymorphic_on: discriminator = row[polymorphic_on] if discriminator is not None: _instance = polymorphic_instances[discriminator] if _instance: return _instance(row, result) # determine identity key if refresh_state: identitykey = refresh_state.key if identitykey is None: # super-rare condition; a refresh is being called # on a non-instance-key instance; this is meant to only # occur within a flush() identitykey = self._identity_key_from_state(refresh_state) else: identitykey = identity_key(row) if identitykey in session_identity_map: instance = session_identity_map[identitykey] state = attributes.instance_state(instance) dict_ = attributes.instance_dict(instance) if self._should_log_debug: self._log_debug("_instance(): using existing instance %s identity %s", instance_str(instance), identitykey) isnew = state.runid != context.runid currentload = not isnew loaded_instance = False if not currentload and version_id_col and context.version_check and \ self._get_state_attr_by_column(state, self.version_id_col) != row[version_id_col]: raise exc.ConcurrentModificationError( "Instance '%s' version of %s does not match %s" % (state_str(state), self._get_state_attr_by_column(state, self.version_id_col), row[version_id_col])) elif refresh_state: # out of band refresh_state detected (i.e. its not in the session.identity_map) # honor it anyway. this can happen if a _get() occurs within save_obj(), such as # when eager_defaults is True. state = refresh_state instance = state.obj() dict_ = attributes.instance_dict(instance) isnew = state.runid != context.runid currentload = True loaded_instance = False else: if self._should_log_debug: self._log_debug("_instance(): identity key %s not in session", identitykey) if self.allow_null_pks: for x in identitykey[1]: if x is not None: break else: return None else: if None in identitykey[1]: return None isnew = True currentload = True loaded_instance = True if create_instance: instance = create_instance(self, context, row, self.class_) if instance is EXT_CONTINUE: instance = self.class_manager.new_instance() else: manager = attributes.manager_of_class(instance.__class__) # TODO: if manager is None, raise a friendly error about # returning instances of unmapped types manager.setup_instance(instance) else: instance = self.class_manager.new_instance() if self._should_log_debug: self._log_debug("_instance(): created new instance %s identity %s", instance_str(instance), identitykey) dict_ = attributes.instance_dict(instance) state = attributes.instance_state(instance) state.key = identitykey # manually adding instance to session. for a complete add, # session._finalize_loaded() must be called. state.session_id = context.session.hash_key session_identity_map.add(state) if currentload or populate_existing: if isnew: state.runid = context.runid context.progress[state] = dict_ if not populate_instance or \ populate_instance(self, context, row, instance, only_load_props=only_load_props, instancekey=identitykey, isnew=isnew) is EXT_CONTINUE: populate_state(state, dict_, row, isnew, only_load_props) else: # populate attributes on non-loading instances which have been expired # TODO: apply eager loads to un-lazy loaded collections ? if state in context.partials or state.unloaded: if state in context.partials: isnew = False (d_, attrs) = context.partials[state] else: isnew = True attrs = state.unloaded context.partials[state] = (dict_, attrs) #<-- allow query.instances to commit the subset of attrs if not populate_instance or \ populate_instance(self, context, row, instance, only_load_props=attrs, instancekey=identitykey, isnew=isnew) is EXT_CONTINUE: populate_state(state, dict_, row, isnew, attrs, instancekey=identitykey) if loaded_instance: state._run_on_load(instance) if result is not None and \ (not append_result or append_result(self, context, row, instance, result, instancekey=identitykey, isnew=isnew) is EXT_CONTINUE): result.append(instance) return instance return _instance def _populators(self, context, path, row, adapter): """Produce a collection of attribute level row processor callables.""" new_populators, existing_populators = [], [] for prop in self._props.itervalues(): newpop, existingpop = prop.create_row_processor(context, path, self, row, adapter) if newpop: new_populators.append((prop.key, newpop)) if existingpop: existing_populators.append((prop.key, existingpop)) return new_populators, existing_populators def _configure_subclass_mapper(self, context, path, adapter): """Produce a mapper level row processor callable factory for mappers inheriting this one.""" def configure_subclass_mapper(discriminator): try: mapper = self.polymorphic_map[discriminator] except KeyError: raise AssertionError("No such polymorphic_identity %r is defined" % discriminator) if mapper is self: return None return mapper._instance_processor(context, path, adapter, polymorphic_from=self) return configure_subclass_mapper log.class_logger(Mapper) def reconstructor(fn): """Decorate a method as the 'reconstructor' hook. Designates a method as the "reconstructor", an ``__init__``-like method that will be called by the ORM after the instance has been loaded from the database or otherwise reconstituted. The reconstructor will be invoked with no arguments. Scalar (non-collection) database-mapped attributes of the instance will be available for use within the function. Eagerly-loaded collections are generally not yet available and will usually only contain the first element. ORM state changes made to objects at this stage will not be recorded for the next flush() operation, so the activity within a reconstructor should be conservative. """ fn.__sa_reconstructor__ = True return fn def validates(*names): """Decorate a method as a 'validator' for one or more named properties. Designates a method as a validator, a method which receives the name of the attribute as well as a value to be assigned, or in the case of a collection to be added to the collection. The function can then raise validation exceptions to halt the process from continuing, or can modify or replace the value before proceeding. The function should otherwise return the given value. """ def wrap(fn): fn.__sa_validators__ = names return fn return wrap def _event_on_init(state, instance, args, kwargs): """Trigger mapper compilation and run init_instance hooks.""" instrumenting_mapper = state.manager.info[_INSTRUMENTOR] # compile() always compiles all mappers instrumenting_mapper.compile() if 'init_instance' in instrumenting_mapper.extension: instrumenting_mapper.extension.init_instance( instrumenting_mapper, instrumenting_mapper.class_, state.manager.events.original_init, instance, args, kwargs) def _event_on_init_failure(state, instance, args, kwargs): """Run init_failed hooks.""" instrumenting_mapper = state.manager.info[_INSTRUMENTOR] if 'init_failed' in instrumenting_mapper.extension: util.warn_exception( instrumenting_mapper.extension.init_failed, instrumenting_mapper, instrumenting_mapper.class_, state.manager.events.original_init, instance, args, kwargs) def _event_on_resurrect(state, instance): # re-populate the primary key elements # of the dict based on the mapping. instrumenting_mapper = state.manager.info[_INSTRUMENTOR] for col, val in zip(instrumenting_mapper.primary_key, state.key[1]): instrumenting_mapper._set_state_attr_by_column(state, col, val) def _sort_states(states): return sorted(states, key=operator.attrgetter('sort_key')) def _load_scalar_attributes(state, attribute_names): """initiate a column-based attribute refresh operation.""" mapper = _state_mapper(state) session = _state_session(state) if not session: raise sa_exc.UnboundExecutionError("Instance %s is not bound to a Session; " "attribute refresh operation cannot proceed" % (state_str(state))) has_key = _state_has_identity(state) result = False if mapper.inherits and not mapper.concrete: statement = mapper._optimized_get_statement(state, attribute_names) if statement: result = session.query(mapper).from_statement(statement)._get(None, only_load_props=attribute_names, refresh_state=state) if result is False: if has_key: identity_key = state.key else: identity_key = mapper._identity_key_from_state(state) result = session.query(mapper)._get(identity_key, refresh_state=state, only_load_props=attribute_names) # if instance is pending, a refresh operation may not complete (even if PK attributes are assigned) if has_key and result is None: raise exc.ObjectDeletedError("Instance '%s' has been deleted." % state_str(state))