# orm/mapper.py # Copyright (C) 2005, 2006, 2007 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 import weakref, warnings, operator from sqlalchemy import sql, util, exceptions, logging from sqlalchemy.sql import expression from sqlalchemy.sql import util as sqlutil from sqlalchemy.orm import util as mapperutil from sqlalchemy.orm.util import ExtensionCarrier, create_row_adapter from sqlalchemy.orm import sync from sqlalchemy.orm.interfaces import MapperProperty, EXT_CONTINUE, SynonymProperty, PropComparator deferred_load = None __all__ = ['Mapper', 'class_mapper', 'object_mapper', 'mapper_registry'] # 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() # lock used to synchronize the "mapper compile" step _COMPILE_MUTEX = util.threading.Lock() # initialize these two lazily attribute_manager = None ColumnProperty = None class Mapper(object): """Define 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, inherit_foreign_keys = 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, polymorphic_fetch=None, concrete=False, select_table=None, allow_null_pks=False, batch=True, column_prefix=None, include_properties=None, exclude_properties=None): """Construct a new mapper. Mappers are normally constructed via the [sqlalchemy.orm#mapper()] function. See for details. """ 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, expression._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_argument = 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.inherit_foreign_keys = inherit_foreign_keys self.extension = extension self._init_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 self.polymorphic_on = polymorphic_on self._eager_loaders = util.Set() self._row_translators = {} # 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 not in (None, 'union', 'select', 'deferred'): raise exceptions.ArgumentError("Invalid option for 'polymorphic_fetch': '%s'" % polymorphic_fetch) if polymorphic_fetch is None: self.polymorphic_fetch = (self.select_table is None) and 'select' or 'union' else: self.polymorphic_fetch = polymorphic_fetch # 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.columns = self.c = util.OrderedProperties() self.include_properties = include_properties self.exclude_properties = exclude_properties # 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 self.__props_init = False self.__should_log_info = logging.is_info_enabled(self.logger) self.__should_log_debug = logging.is_debug_enabled(self.logger) self._compile_class() self._compile_extensions() self._compile_inheritance() self._compile_tables() self._compile_properties() self._compile_selectable() self.__log("constructed") def __log(self, msg): if self.__should_log_info: 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.description or str(self.local_table)) + (not self._is_primary_mapper() and "|non-primary" or "") + ") " + msg) def __log_debug(self, msg): if self.__should_log_debug: 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.description 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 attribute_manager.has_parent(klass, obj, key, optimistic=optimistic): return False else: if 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_property(self, key, resolve_synonyms=False, raiseerr=True): """return MapperProperty with the given key.""" 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 exceptions.InvalidRequestError("Mapper '%s' has no property '%s'" % (str(self), key)) return prop def iterate_properties(self): return self.__props.itervalues() iterate_properties = property(iterate_properties, doc="returns an iterator of all MapperProperty objects.") def properties(self): raise NotImplementedError("Public collection of MapperProperty objects is provided by the get_property() and iterate_properties accessors.") properties = property(properties) def dispose(self): # disaable any attribute-based compilation self.__props_init = True if hasattr(self.class_, 'c'): del self.class_.c attribute_manager.unregister_class(self.class_) def compile(self): """Compile this mapper into its final internal format. """ if self.__props_init: return self _COMPILE_MUTEX.acquire() try: # double-check inside mutex if self.__props_init: return self # initialize properties on all mappers for mapper in mapper_registry.values(): if not mapper.__props_init: mapper.__initialize_properties() # if we're not primary, compile us if self.non_primary: self.__initialize_properties() return self finally: _COMPILE_MUTEX.release() def _check_compile(self): if self.non_primary and not self.__props_init: self.__initialize_properties() return self def __initialize_properties(self): """Call the ``init()`` method on all ``MapperProperties`` attached to this mapper. This happens after all mappers have completed compiling everything else up until this point, so that all dependencies are fully available. """ 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_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 is not None: for ext_obj in util.to_list(extension): # local MapperExtensions have already instrumented the class extlist.add(ext_obj) for ext in global_extensions: if isinstance(ext, type): ext = ext() extlist.add(ext) ext.instrument_class(self, self.class_) self.extension = ExtensionCarrier() for ext in extlist: self.extension.append(ext) def _compile_inheritance(self): """Determine 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) else: self.inherits = self.inherits 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) if self.inherit_foreign_keys: fks = util.Set(self.inherit_foreign_keys) else: fks = None self._synchronizer.compile(self.mapped_table.onclause, foreign_keys=fks) 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: if self.inherits.polymorphic_on is not None: self.polymorphic_on = self.mapped_table.corresponding_column(self.inherits.polymorphic_on, raiseerr=False) else: raise exceptions.ArgumentError("Mapper '%s' specifies a polymorphic_identity of '%s', but no mapper in it's hierarchy specifies the 'polymorphic_on' column argument" % (str(self), self.polymorphic_identity)) if self.polymorphic_identity is not None and not self.concrete: self._identity_class = self.inherits._identity_class else: self._identity_class = self.class_ 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) self.base_mapper = self.inherits.base_mapper self._all_tables = self.inherits._all_tables else: self._all_tables = util.Set() self.base_mapper = self self._synchronizer = None self.mapped_table = self.local_table if self.polymorphic_identity is not None: if self.polymorphic_on is None: raise exceptions.ArgumentError("Mapper '%s' specifies a polymorphic_identity of '%s', but no mapper in it's hierarchy specifies the 'polymorphic_on' column argument" % (str(self), self.polymorphic_identity)) self._add_polymorphic_mapping(self.polymorphic_identity, self) self._identity_class = self.class_ 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): """Add 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, set up some more table-based instance variables and determine 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 # 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 # locate all tables contained within the "table" passed in, which # may be a join or other construct self.tables = sqlutil.TableFinder(self.mapped_table) if not self.tables: raise exceptions.InvalidRequestError("Could not find any Table objects in mapped table '%s'" % str(self.mapped_table)) # determine primary key columns self.pks_by_table = {} # go through all of our represented tables # and assemble primary key columns for t in self.tables + [self.mapped_table]: self._all_tables.add(t) try: l = self.pks_by_table[t] except KeyError: l = self.pks_by_table.setdefault(t, util.OrderedSet()) for k in t.primary_key: l.add(k) if self.primary_key_argument is not None: for k in self.primary_key_argument: self.pks_by_table.setdefault(k.table, util.OrderedSet()).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)) if self.inherits is not None and not self.concrete and not self.primary_key_argument: self.primary_key = self.inherits.primary_key self._get_clause = self.inherits._get_clause self._equivalent_columns = {} else: # create the "primary_key" for this mapper. this will flatten "equivalent" primary key columns # into one column, where "equivalent" means that one column references the other via foreign key, or # multiple columns that all reference a common parent column. it will also resolve the column # against the "mapped_table" of this mapper. self._equivalent_columns = self._get_equivalent_columns() primary_key = expression.ColumnSet() for col in (self.primary_key_argument or self.pks_by_table[self.mapped_table]): c = self.mapped_table.corresponding_column(col, raiseerr=False) if c is None: for cc in self._equivalent_columns[col]: c = self.mapped_table.corresponding_column(cc, raiseerr=False) if c is not None: break else: raise exceptions.ArgumentError("Cant resolve column " + str(col)) # this step attempts to resolve the column to an equivalent which is not # a foreign key elsewhere. this helps with joined table inheritance # so that PKs are expressed in terms of the base table which is always # present in the initial select # TODO: this is a little hacky right now, the "tried" list is to prevent # endless loops between cyclical FKs, try to make this cleaner/work better/etc., # perhaps via topological sort (pick the leftmost item) tried = util.Set() while True: if not len(c.foreign_keys) or c in tried: break for cc in c.foreign_keys: cc = cc.column c2 = self.mapped_table.corresponding_column(cc, raiseerr=False) if c2 is not None: c = c2 tried.add(c) break else: break primary_key.add(c) if len(primary_key) == 0: raise exceptions.ArgumentError("Could not assemble any primary key columns for mapped table '%s'" % (self.mapped_table.name)) self.primary_key = primary_key self.__log("Identified primary key columns: " + str(primary_key)) _get_clause = sql.and_() _get_params = {} for primary_key in self.primary_key: bind = sql.bindparam(None, type_=primary_key.type) _get_params[primary_key] = bind _get_clause.clauses.append(primary_key == bind) self._get_clause = (_get_clause, _get_params) def _get_equivalent_columns(self): """Create a map of all *equivalent* columns, based on the determination of column pairs that are equated to one another either by an established foreign key relationship or by a joined-table inheritance join. This is used to determine the minimal set of primary key columns for the mapper, as well as when relating columns to those of a polymorphic selectable (i.e. a UNION of several mapped tables), as that selectable usually only contains one column in its columns clause out of a group of several which are equated to each other. 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 = {} def visit_binary(binary): if binary.operator == operator.eq: if binary.left in result: result[binary.left].add(binary.right) else: result[binary.left] = util.Set([binary.right]) if binary.right in result: result[binary.right].add(binary.left) else: result[binary.right] = util.Set([binary.left]) vis = mapperutil.BinaryVisitor(visit_binary) for mapper in self.base_mapper.polymorphic_iterator(): if mapper.inherit_condition is not None: vis.traverse(mapper.inherit_condition) # TODO: matching of cols to foreign keys might better be generalized # into general column translation (i.e. corresponding_column) # recursively descend into the foreign key collection of the given column # and assemble each FK-related col as an "equivalent" for the given column def equivs(col, recursive, equiv): if col in recursive: return recursive.add(col) for fk in col.foreign_keys: result.setdefault(fk.column, util.Set()).add(equiv) equivs(fk.column, recursive, col) for column in (self.primary_key_argument or self.pks_by_table[self.mapped_table]): for col in column.proxy_set: if not col.foreign_keys: result.setdefault(col, util.Set()).add(col) else: equivs(col, util.Set(), col) return result class _CompileOnAttr(PropComparator): """placeholder class attribute which fires mapper compilation on access""" def __init__(self, class_, key): self.class_ = class_ self.key = key def __getattribute__(self, key): cls = object.__getattribute__(self, 'class_') clskey = object.__getattribute__(self, 'key') if key.startswith('__'): return object.__getattribute__(self, key) class_mapper(cls) if cls.__dict__.get(clskey) is self: # FIXME: there should not be any scenarios where # a mapper compile leaves this CompileOnAttr in # place. warnings.warn(RuntimeWarning("Attribute '%s' on class '%s' was not replaced during mapper compilation operation" % (clskey, cls.__name__))) # clean us up explicitly delattr(cls, clskey) return getattr(getattr(cls, clskey), key) def _compile_properties(self): """Inspect the properties dictionary sent to the Mapper's constructor as well as the mapped_table, and create ``MapperProperty`` objects corresponding to each mapped column and relation. """ # 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 = mapperutil.TranslatingDict(self.mapped_table) # load custom properties if self._init_properties is not None: for key, prop in self._init_properties.iteritems(): self._compile_property(key, prop, False) # pull properties from the inherited mapper if any. if self.inherits is not None: for key, prop in self.inherits.__props.iteritems(): if key not in self.__props: self._adapt_inherited_property(key, prop) # 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 if (self.include_properties is not None and column.key not in self.include_properties): self.__log("not including property %s" % (column.key)) continue if (self.exclude_properties is not None and column.key in self.exclude_properties): self.__log("excluding property %s" % (column.key)) continue column_key = (self.column_prefix or '') + column.key self._compile_property(column_key, column, init=False, setparent=True) def _adapt_inherited_property(self, key, prop): if not self.concrete: self._compile_property(key, prop, init=False, setparent=False) # TODO: concrete properties dont adapt at all right now....will require copies of relations() etc. def _compile_property(self, key, prop, init=True, setparent=True): self.__log("_compile_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 exceptions.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 column in self.primary_key and prop.columns[-1] in self.primary_key: warnings.warn(RuntimeWarning("On mapper %s, primary key column '%s' is being combined with distinct primary key column '%s' in attribute '%s'. Use explicit properties to give each column its own mapped attribute name." % (str(self), str(column), str(prop.columns[-1]), key))) 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: mapped_column = [] for c in columns: mc = self.mapped_table.corresponding_column(c, raiseerr=False) if not mc: raise exceptions.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." % str(c)) mapped_column.append(mc) prop = ColumnProperty(*mapped_column) 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: return if isinstance(prop, ColumnProperty): # relate the mapper's "select table" to the given ColumnProperty col = self.select_table.corresponding_column(prop.columns[0], raiseerr=False) # 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] self.columns[key] = col for col in prop.columns: self._columntoproperty[col] = prop self.__props[key] = prop if setparent: prop.set_parent(self) # TODO: centralize _CompileOnAttr logic, move into MapperProperty classes if (not isinstance(prop, SynonymProperty) or prop.proxy) and not self.non_primary and not hasattr(self.class_, key): setattr(self.class_, key, Mapper._CompileOnAttr(self.class_, key)) if init: prop.init(key, self) for mapper in self._inheriting_mappers: mapper._adapt_inherited_property(key, prop) 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. Currently, non-column properties are **not** copied. This implies that a polymorphic mapper can't do any eager loading right now. """ if self.select_table is not self.mapped_table: props = {} if self._init_properties is not None: for key, prop in self._init_properties.iteritems(): if expression.is_column(prop): props[key] = self.select_table.corresponding_column(prop) elif (isinstance(prop, list) and expression.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), primary_key=self.primary_key_argument) 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 decorate the `__init__` method on the mapped class to include optional auto-session attachment logic. """ if self.non_primary: return if not self.non_primary and (self.class_key in mapper_registry): 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. clear_mappers() will remove *all* current mappers from all classes." % (self.class_, self.entity_name)) def extra_init(class_, oldinit, instance, args, kwargs): self.compile() if 'init_instance' in self.extension.methods: self.extension.init_instance(self, class_, oldinit, instance, args, kwargs) def on_exception(class_, oldinit, instance, args, kwargs): util.warn_exception(self.extension.init_failed, self, class_, oldinit, instance, args, kwargs) attribute_manager.register_class(self.class_, extra_init=extra_init, on_exception=on_exception) _COMPILE_MUTEX.acquire() try: mapper_registry[self.class_key] = self finally: _COMPILE_MUTEX.release() for ext in util.to_list(self.extension, []): ext.instrument_class(self, self.class_) if self.entity_name is None: self.class_.c = self.c 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): """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()``.""" yield self for mapper in self._inheriting_mappers: for m in mapper.polymorphic_iterator(): yield m 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 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._init_properties[key] = prop self._compile_property(key, prop, init=self.__props_init) 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.description or str(self.local_table)) + (not self._is_primary_mapper() and "|non-primary" or "") def _is_primary_mapper(self): """Return True if this mapper is the primary mapper for its class key (class + entity_name).""" # FIXME: cant we just look at "non_primary" flag ? return mapper_registry.get(self.class_key, None) is self def primary_mapper(self): """Return 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. Raise ``InvalidRequestError`` if a session cannot be retrieved from the extension chain. """ if 'get_session' in self.extension.methods: s = self.extension.get_session() if s is not EXT_CONTINUE: return s 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.") 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.engine.base.RowProxy`` instance or a dictionary corresponding result-set ``ColumnElement`` instances to their values within a row. """ return (self._identity_class, tuple([row[column] for column in self.primary_key]), 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._identity_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.primary_key] def canload(self, instance): """return true if this mapper is capable of loading the given instance""" if self.polymorphic_on is not None: return isinstance(instance, self.class_) else: return instance.__class__ is self.class_ 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 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 return prop.getattr(obj, column) 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].setattr(obj, value, column) 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. """ 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 obj in objects: self.save_obj([obj], uowtransaction, postupdate=postupdate, post_update_cols=post_update_cols, single=True) return if 'connection_callable' in uowtransaction.mapper_flush_opts: connection_callable = uowtransaction.mapper_flush_opts['connection_callable'] tups = [(obj, connection_callable(self, obj)) for obj in objects] else: connection = uowtransaction.transaction.connection(self) tups = [(obj, connection) for obj in objects] if not postupdate: for obj, connection in tups: if not has_identity(obj): for mapper in object_mapper(obj).iterate_to_root(): if 'before_insert' in mapper.extension.methods: mapper.extension.before_insert(mapper, connection, obj) else: for mapper in object_mapper(obj).iterate_to_root(): if 'before_update' in mapper.extension.methods: mapper.extension.before_update(mapper, connection, obj) for obj, connection 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. mapper = object_mapper(obj) instance_key = mapper.identity_key_from_instance(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))) if self.__should_log_debug: 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.set_row_switch(existing) if has_identity(obj): if obj._instance_key != instance_key: raise exceptions.FlushError("Can't change the identity of instance %s in session (existing identity: %s; new identity: %s)" % (mapperutil.instance_str(obj), obj._instance_key, instance_key)) 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, connection in tups: mapper = object_mapper(obj) if table not in mapper.tables or not mapper._has_pks(table): continue instance_key = mapper.identity_key_from_instance(obj) if self.__should_log_debug: 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 = {} value_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. "_" 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: 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 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 a: if isinstance(a[0], sql.ClauseElement): value_params[col] = a[0] else: params[col.key] = prop.get_col_value(col, 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: # TODO: clauseelments as bind params should # be handled by Insert/Update expression upon execute() if isinstance(value, sql.ClauseElement): value_params[col] = value else: 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, connection, value_params)) else: insert.append((obj, 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, unique=True)) 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, unique=True)) 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, connection, value_params) = rec c = connection.execute(statement.values(value_params), params) mapper._postfetch(connection, table, obj, c, c.last_updated_params(), value_params) # testlib.pragma exempt:__hash__ updated_objects.add((id(obj), obj, connection)) rows += c.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 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, connection, value_params) = rec c = connection.execute(statement.values(value_params), 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(), value_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) # testlib.pragma exempt:__hash__ inserted_objects.add((id(obj), obj, connection)) if not postupdate: for id_, obj, connection in inserted_objects: for mapper in object_mapper(obj).iterate_to_root(): if 'after_insert' in mapper.extension.methods: mapper.extension.after_insert(mapper, connection, obj) for id_, obj, connection in updated_objects: for mapper in object_mapper(obj).iterate_to_root(): if 'after_update' in mapper.extension.methods: mapper.extension.after_update(mapper, connection, obj) def _postfetch(self, connection, table, obj, resultproxy, params, value_params): """After an ``INSERT`` or ``UPDATE``, assemble newly generated values on an instance. For columns which are marked as being generated on the database side, set up a group-based "deferred" loader which will populate those attributes in one query when next accessed. """ postfetch_cols = resultproxy.postfetch_cols().union(util.Set(value_params.keys())) deferred_props = [] for c in table.c: if c in postfetch_cols and (not c.key in params or c in value_params): prop = self._getpropbycolumn(c, raiseerror=False) if prop is None: continue deferred_props.append(prop.key) continue if c.primary_key or not c.key in params: continue v = self.get_attr_by_column(obj, c, False) if v is NO_ATTRIBUTE: continue elif v != params[c.key]: self.set_attr_by_column(obj, c, params[c.key]) if deferred_props: expire_instance(obj, deferred_props) 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. """ 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 = [(obj, connection_callable(self, obj)) for obj in objects] else: connection = uowtransaction.transaction.connection(self) tups = [(obj, connection) for obj in objects] for (obj, connection) in tups: for mapper in object_mapper(obj).iterate_to_root(): if 'before_delete' in mapper.extension.methods: mapper.extension.before_delete(mapper, connection, obj) deleted_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=True): delete = {} for (obj, connection) in tups: mapper = object_mapper(obj) if table not in mapper.tables or not mapper._has_pks(table): continue params = {} if not hasattr(obj, '_instance_key'): continue else: delete.setdefault(connection, []).append(params) for col in mapper.pks_by_table[table]: params[col.key] = mapper.get_attr_by_column(obj, col) if mapper.version_id_col is not None: params[mapper.version_id_col.key] = mapper.get_attr_by_column(obj, mapper.version_id_col) # testlib.pragma exempt:__hash__ deleted_objects.add((id(obj), obj, connection)) for connection, del_objects in delete.iteritems(): mapper = table_to_mapper[table] def comparator(a, b): for col in mapper.pks_by_table[table]: x = cmp(a[col.key],b[col.key]) if x != 0: return x return 0 del_objects.sort(comparator) clause = sql.and_() for col in mapper.pks_by_table[table]: clause.clauses.append(col == sql.bindparam(col.key, type_=col.type, unique=True)) if mapper.version_id_col is not None: clause.clauses.append(mapper.version_id_col == sql.bindparam(mapper.version_id_col.key, type_=mapper.version_id_col.type, unique=True)) statement = table.delete(clause) c = connection.execute(statement, del_objects) if c.supports_sane_multi_rowcount() and c.rowcount != len(del_objects): raise exceptions.ConcurrentModificationError("Deleted rowcount %d does not match number of objects deleted %d" % (c.rowcount, len(del_objects))) for id_, obj, connection in deleted_objects: for mapper in object_mapper(obj).iterate_to_root(): if 'after_delete' in mapper.extension.methods: mapper.extension.after_delete(mapper, connection, obj) def _has_pks(self, table): try: pk = self.pks_by_table[table] if not pk: return False for k in pk: if k not in self._columntoproperty: return False else: return True except KeyError: return False def register_dependencies(self, uowcommit, *args, **kwargs): """Register ``DependencyProcessor`` instances with a ``unitofwork.UOWTransaction``. This call `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, halt_on=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.IdentitySet() for prop in self.__props.values(): for c in prop.cascade_iterator(type, object, recursive, halt_on=halt_on): yield c def cascade_callable(self, type, object, callable_, recursive=None, halt_on=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.IdentitySet() for prop in self.__props.values(): prop.cascade_callable(type, object, callable_, recursive, halt_on=halt_on) 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, skip_polymorphic=False, extension=None, only_load_props=None, refresh_instance=None): """Pull an object instance from the given row and append it to the given result list. If the instance already exists in the given identity map, its not added. In either case, execute all the property loaders on the instance to also process extra information in the row. """ if not extension: extension = self.extension if 'translate_row' in extension.methods: ret = extension.translate_row(self, context, row) if ret is not EXT_CONTINUE: row = ret if refresh_instance is None: if not skip_polymorphic and self.polymorphic_on is not None: discriminator = row[self.polymorphic_on] if discriminator is not None: mapper = self.polymorphic_map[discriminator] if mapper is not self: if ('polymorphic_fetch', mapper) not in context.attributes: context.attributes[('polymorphic_fetch', mapper)] = (self, [t for t in mapper.tables if t not in self.tables]) row = self.translate_row(mapper, row) return mapper._instance(context, row, result=result, skip_polymorphic=True) # determine identity key if refresh_instance: identitykey = refresh_instance._instance_key else: identitykey = self.identity_key_from_row(row) (session_identity_map, local_identity_map) = (context.session.identity_map, context.identity_map) # look in main identity map. if present, we only populate # if repopulate flags are set. this block returns the instance. if identitykey in session_identity_map: instance = session_identity_map[identitykey] if self.__should_log_debug: 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 context.populate_existing or self.always_refresh or instance._state.trigger is not None: instance._state.trigger = None if identitykey not in local_identity_map: local_identity_map[identitykey] = instance isnew = True if 'populate_instance' not in extension.methods or extension.populate_instance(self, context, row, instance, instancekey=identitykey, isnew=isnew, only_load_props=only_load_props) is EXT_CONTINUE: self.populate_instance(context, instance, row, instancekey=identitykey, isnew=isnew, only_load_props=only_load_props) if 'append_result' not in extension.methods or extension.append_result(self, context, row, instance, result, instancekey=identitykey, isnew=isnew) is EXT_CONTINUE: if result is not None: result.append(instance) return instance elif self.__should_log_debug: self.__log_debug("_instance(): identity key %s not in session" % str(identitykey)) # look in identity map which is local to this load operation if identitykey not in local_identity_map: # check that sufficient primary key columns are present 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 x in identitykey[1]: if x 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. if None in identitykey[1]: return None if 'create_instance' in extension.methods: instance = extension.create_instance(self, context, row, self.class_) if instance is EXT_CONTINUE: instance = attribute_manager.new_instance(self.class_) else: instance = attribute_manager.new_instance(self.class_) instance._entity_name = self.entity_name instance._instance_key = identitykey if self.__should_log_debug: self.__log_debug("_instance(): created new instance %s identity %s" % (mapperutil.instance_str(instance), str(identitykey))) local_identity_map[identitykey] = instance isnew = True else: # instance is already present instance = local_identity_map[identitykey] isnew = False # populate. note that we still call this for an instance already loaded as additional collection state is present # in subsequent rows (i.e. eagerly loaded collections) flags = {'instancekey':identitykey, 'isnew':isnew} if 'populate_instance' not in extension.methods or extension.populate_instance(self, context, row, instance, only_load_props=only_load_props, **flags) is EXT_CONTINUE: self.populate_instance(context, instance, row, only_load_props=only_load_props, **flags) if 'append_result' not in extension.methods or extension.append_result(self, context, row, instance, result, **flags) is EXT_CONTINUE: if result is not None: result.append(instance) return instance def _deferred_inheritance_condition(self, base_mapper, needs_tables): def visit_binary(binary): leftcol = binary.left rightcol = binary.right if leftcol is None or rightcol is None: return if leftcol.table not in needs_tables: binary.left = sql.bindparam(leftcol.name, None, type_=binary.right.type, unique=True) param_names.append(leftcol) elif rightcol not in needs_tables: binary.right = sql.bindparam(rightcol.name, None, type_=binary.right.type, unique=True) param_names.append(rightcol) allconds = [] param_names = [] visitor = mapperutil.BinaryVisitor(visit_binary) for mapper in self.iterate_to_root(): if mapper is base_mapper: break allconds.append(visitor.traverse(mapper.inherit_condition, clone=True)) return sql.and_(*allconds), param_names 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. """ if tomapper in self._row_translators: # row translators are cached based on target mapper return self._row_translators[tomapper](row) else: translator = create_row_adapter(self.mapped_table, tomapper.mapped_table, equivalent_columns=self._equivalent_columns) self._row_translators[tomapper] = translator return translator(row) def populate_instance(self, selectcontext, instance, row, ispostselect=None, isnew=False, only_load_props=None, **flags): """populate an instance from a result row.""" snapshot = selectcontext.path + (self,) # retrieve a set of "row population" functions derived from the MapperProperties attached # to this Mapper. These are keyed in the select context based primarily off the # "snapshot" of the stack, which represents a path from the lead mapper in the query to this one, # including relation() names. the key also includes "self", and allows us to distinguish between # other mappers within our inheritance hierarchy (new_populators, existing_populators) = selectcontext.attributes.get(('populators', self, snapshot, ispostselect), (None, None)) if new_populators is None: # no populators; therefore this is the first time we are receiving a row for # this result set. issue create_row_processor() on all MapperProperty objects # and cache in the select context. new_populators = [] existing_populators = [] post_processors = [] for prop in self.__props.values(): if only_load_props and prop.key not in only_load_props: continue (newpop, existingpop, post_proc) = selectcontext.exec_with_path(self, prop.key, prop.create_row_processor, selectcontext, self, row) if newpop is not None: new_populators.append((prop.key, newpop)) if existingpop is not None: existing_populators.append((prop.key, existingpop)) if post_proc is not None: post_processors.append(post_proc) # install a post processor for immediate post-load of joined-table inheriting mappers poly_select_loader = self._get_poly_select_loader(selectcontext, row) if poly_select_loader is not None: post_processors.append(poly_select_loader) selectcontext.attributes[('populators', self, snapshot, ispostselect)] = (new_populators, existing_populators) selectcontext.attributes[('post_processors', self, ispostselect)] = post_processors if isnew or ispostselect: populators = new_populators else: populators = existing_populators for (key, populator) in populators: selectcontext.exec_with_path(self, key, populator, instance, row, ispostselect=ispostselect, isnew=isnew, **flags) if self.non_primary: selectcontext.attributes[('populating_mapper', id(instance))] = self def _post_instance(self, selectcontext, instance): post_processors = selectcontext.attributes[('post_processors', self, None)] for p in post_processors: p(instance) def _get_poly_select_loader(self, selectcontext, row): # 'select' or 'union'+col not present (hosted_mapper, needs_tables) = selectcontext.attributes.get(('polymorphic_fetch', self), (None, None)) if hosted_mapper is None or len(needs_tables)==0 or hosted_mapper.polymorphic_fetch == 'deferred': return cond, param_names = self._deferred_inheritance_condition(hosted_mapper, needs_tables) statement = sql.select(needs_tables, cond, use_labels=True) def post_execute(instance, **flags): self.__log_debug("Post query loading instance " + mapperutil.instance_str(instance)) identitykey = self.identity_key_from_instance(instance) params = {} for c in param_names: params[c.name] = self.get_attr_by_column(instance, c) row = selectcontext.session.connection(self).execute(statement, params).fetchone() self.populate_instance(selectcontext, instance, row, isnew=False, instancekey=identitykey, ispostselect=True) return post_execute Mapper.logger = logging.class_logger(Mapper) class ClassKey(object): """Key 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 self._hash = hash((self.class_, self.entity_name)) def __hash__(self): return self._hash 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): """Return True if the given object has had a mapper association set up, either through loading, or via insertion in a session. """ return hasattr(object, '_entity_name') def identity_equal(a, b): if a is b: return True id_a = getattr(a, '_instance_key', None) id_b = getattr(b, '_instance_key', None) if id_a is None or id_b is None: return False return id_a == id_b def object_mapper(object, entity_name=None, raiseerror=True): """Given an object, return the primary Mapper associated with the object instance. object The object instance. entity_name Entity name of the mapper to retrieve, if the given instance is transient. Otherwise uses the entity name already associated with the instance. raiseerror Defaults to True: raise an ``InvalidRequestError`` if no mapper can be located. If False, return None. """ try: mapper = mapper_registry[ClassKey(object.__class__, getattr(object, '_entity_name', entity_name))] 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', entity_name))) else: return None return mapper def class_mapper(class_, entity_name=None, compile=True): """Given a class and optional entity_name, return the primary Mapper associated with the key. If no mapper can be located, raises ``InvalidRequestError``. """ 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