django1/django/db/__init__.py

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from django.core import signals
from django.db.utils import (DEFAULT_DB_ALIAS, DJANGO_VERSION_PICKLE_KEY,
DataError, OperationalError, IntegrityError, InternalError, ProgrammingError,
NotSupportedError, DatabaseError, InterfaceError, Error, ConnectionHandler,
ConnectionRouter)
__all__ = [
'backend', 'connection', 'connections', 'router', 'DatabaseError',
'IntegrityError', 'InternalError', 'ProgrammingError', 'DataError',
'NotSupportedError', 'Error', 'InterfaceError', 'OperationalError',
'DEFAULT_DB_ALIAS', 'DJANGO_VERSION_PICKLE_KEY'
]
connections = ConnectionHandler()
router = ConnectionRouter()
# `connection`, `DatabaseError` and `IntegrityError` are convenient aliases
# for backend bits.
# DatabaseWrapper.__init__() takes a dictionary, not a settings module, so we
# manually create the dictionary from the settings, passing only the settings
# that the database backends care about.
# We load all these up for backwards compatibility, you should use
# connections['default'] instead.
class DefaultConnectionProxy(object):
"""
Proxy for accessing the default DatabaseWrapper object's attributes. If you
need to access the DatabaseWrapper object itself, use
connections[DEFAULT_DB_ALIAS] instead.
"""
def __getattr__(self, item):
return getattr(connections[DEFAULT_DB_ALIAS], item)
def __setattr__(self, name, value):
return setattr(connections[DEFAULT_DB_ALIAS], name, value)
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def __delattr__(self, name):
return delattr(connections[DEFAULT_DB_ALIAS], name)
def __eq__(self, other):
return connections[DEFAULT_DB_ALIAS] == other
def __ne__(self, other):
return connections[DEFAULT_DB_ALIAS] != other
connection = DefaultConnectionProxy()
# Register an event to reset saved queries when a Django request is started.
def reset_queries(**kwargs):
for conn in connections.all():
conn.queries_log.clear()
signals.request_started.connect(reset_queries)
# Register an event to reset transaction state and close connections past
# their lifetime.
def close_old_connections(**kwargs):
for conn in connections.all():
conn.close_if_unusable_or_obsolete()
signals.request_started.connect(close_old_connections)
signals.request_finished.connect(close_old_connections)