# exc.py - ORM exceptions
# Copyright (C) the SQLAlchemy authors and contributors
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""SQLAlchemy ORM exceptions."""
import sqlalchemy as sa
NO_STATE = (AttributeError, KeyError)
"""Exception types that may be raised by instrumentation implementations."""
class ConcurrentModificationError(sa.exc.SQLAlchemyError):
"""Rows have been modified outside of the unit of work."""
class FlushError(sa.exc.SQLAlchemyError):
"""A invalid condition was detected during flush()."""
class UnmappedError(sa.exc.InvalidRequestError):
"""TODO"""
class DetachedInstanceError(sa.exc.SQLAlchemyError):
"""An attempt to access unloaded attributes on a mapped instance that is detached."""
class UnmappedInstanceError(UnmappedError):
"""An mapping operation was requested for an unknown instance."""
def __init__(self, obj, msg=None):
if not msg:
try:
mapper = sa.orm.class_mapper(type(obj))
name = _safe_cls_name(type(obj))
msg = ("Class %r is mapped, but this instance lacks "
"instrumentation. This occurs when the instance is created "
"before sqlalchemy.orm.mapper(%s) was called." % (name, name))
except UnmappedClassError:
msg = _default_unmapped(type(obj))
if isinstance(obj, type):
msg += (
'; was a class (%s) supplied where an instance was '
'required?' % _safe_cls_name(obj))
UnmappedError.__init__(self, msg)
class UnmappedClassError(UnmappedError):
"""An mapping operation was requested for an unknown class."""
def __init__(self, cls, msg=None):
if not msg:
msg = _default_unmapped(cls)
UnmappedError.__init__(self, msg)
class ObjectDeletedError(sa.exc.InvalidRequestError):
"""An refresh() operation failed to re-retrieve an object's row."""
class UnmappedColumnError(sa.exc.InvalidRequestError):
"""Mapping operation was requested on an unknown column."""
class NoResultFound(sa.exc.InvalidRequestError):
"""A database result was required but none was found."""
class MultipleResultsFound(sa.exc.InvalidRequestError):
"""A single database result was required but more than one were found."""
# Legacy compat until 0.6.
sa.exc.ConcurrentModificationError = ConcurrentModificationError
sa.exc.FlushError = FlushError
sa.exc.UnmappedColumnError
def _safe_cls_name(cls):
try:
cls_name = '.'.join((cls.__module__, cls.__name__))
except AttributeError:
cls_name = getattr(cls, '__name__', None)
if cls_name is None:
cls_name = repr(cls)
return cls_name
def _default_unmapped(cls):
try:
mappers = sa.orm.attributes.manager_of_class(cls).mappers
except NO_STATE:
mappers = {}
except TypeError:
mappers = {}
name = _safe_cls_name(cls)
if not mappers:
return "Class '%s' is not mapped" % name
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