Repository URL to install this package:
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Version:
4.0.111 ▾
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YZ d S( s Core event interfaces.i ( t eventt exc( t Pool( t Connectablet Enginet Dialect( t SchemaEventTargett DDLEventsc B sY e Z d Z d Z e Z d Z d Z d Z d Z d Z
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Define event listeners for schema objects,
that is, :class:`.SchemaItem` and other :class:`.SchemaEventTarget`
subclasses, including :class:`.MetaData`, :class:`.Table`,
:class:`.Column`.
:class:`.MetaData` and :class:`.Table` support events
specifically regarding when CREATE and DROP
DDL is emitted to the database.
Attachment events are also provided to customize
behavior whenever a child schema element is associated
with a parent, such as, when a :class:`.Column` is associated
with its :class:`.Table`, when a :class:`.ForeignKeyConstraint`
is associated with a :class:`.Table`, etc.
Example using the ``after_create`` event::
from sqlalchemy import event
from sqlalchemy import Table, Column, Metadata, Integer
m = MetaData()
some_table = Table('some_table', m, Column('data', Integer))
def after_create(target, connection, **kw):
connection.execute("ALTER TABLE %s SET name=foo_%s" %
(target.name, target.name))
event.listen(some_table, "after_create", after_create)
DDL events integrate closely with the
:class:`.DDL` class and the :class:`.DDLElement` hierarchy
of DDL clause constructs, which are themselves appropriate
as listener callables::
from sqlalchemy import DDL
event.listen(
some_table,
"after_create",
DDL("ALTER TABLE %(table)s SET name=foo_%(table)s")
)
The methods here define the name of an event as well
as the names of members that are passed to listener
functions.
See also:
:ref:`event_toplevel`
:class:`.DDLElement`
:class:`.DDL`
:ref:`schema_ddl_sequences`
t SomeSchemaClassOrObjectc K s d S( s_ Called before CREATE statements are emitted.
:param target: the :class:`.MetaData` or :class:`.Table`
object which is the target of the event.
:param connection: the :class:`.Connection` where the
CREATE statement or statements will be emitted.
:param \**kw: additional keyword arguments relevant
to the event. The contents of this dictionary
may vary across releases, and include the
list of tables being generated for a metadata-level
event, the checkfirst flag, and other
elements used by internal events.
N( ( t selft targett
connectiont kw( ( sF /home/tvault/.virtenv/lib/python2.7/site-packages/sqlalchemy/events.pyt
before_createN s c K s d S( s` Called after CREATE statements are emitted.
:param target: the :class:`.MetaData` or :class:`.Table`
object which is the target of the event.
:param connection: the :class:`.Connection` where the
CREATE statement or statements have been emitted.
:param \**kw: additional keyword arguments relevant
to the event. The contents of this dictionary
may vary across releases, and include the
list of tables being generated for a metadata-level
event, the checkfirst flag, and other
elements used by internal events.
N( ( R R
R R ( ( sF /home/tvault/.virtenv/lib/python2.7/site-packages/sqlalchemy/events.pyt after_create^ s c K s d S( s[ Called before DROP statements are emitted.
:param target: the :class:`.MetaData` or :class:`.Table`
object which is the target of the event.
:param connection: the :class:`.Connection` where the
DROP statement or statements will be emitted.
:param \**kw: additional keyword arguments relevant
to the event. The contents of this dictionary
may vary across releases, and include the
list of tables being generated for a metadata-level
event, the checkfirst flag, and other
elements used by internal events.
N( ( R R
R R ( ( sF /home/tvault/.virtenv/lib/python2.7/site-packages/sqlalchemy/events.pyt before_dropn s c K s d S( s\ Called after DROP statements are emitted.
:param target: the :class:`.MetaData` or :class:`.Table`
object which is the target of the event.
:param connection: the :class:`.Connection` where the
DROP statement or statements have been emitted.
:param \**kw: additional keyword arguments relevant
to the event. The contents of this dictionary
may vary across releases, and include the
list of tables being generated for a metadata-level
event, the checkfirst flag, and other
elements used by internal events.
N( ( R R
R R ( ( sF /home/tvault/.virtenv/lib/python2.7/site-packages/sqlalchemy/events.pyt
after_drop~ s c C s d S( s
Called before a :class:`.SchemaItem` is associated with
a parent :class:`.SchemaItem`.
:param target: the target object
:param parent: the parent to which the target is being attached.
:func:`.event.listen` also accepts a modifier for this event:
:param propagate=False: When True, the listener function will
be established for any copies made of the target object,
i.e. those copies that are generated when
:meth:`.Table.tometadata` is used.
N( ( R R
t parent( ( sF /home/tvault/.virtenv/lib/python2.7/site-packages/sqlalchemy/events.pyt before_parent_attach s c C s d S( s Called after a :class:`.SchemaItem` is associated with
a parent :class:`.SchemaItem`.
:param target: the target object
:param parent: the parent to which the target is being attached.
:func:`.event.listen` also accepts a modifier for this event:
:param propagate=False: When True, the listener function will
be established for any copies made of the target object,
i.e. those copies that are generated when
:meth:`.Table.tometadata` is used.
N( ( R R
R ( ( sF /home/tvault/.virtenv/lib/python2.7/site-packages/sqlalchemy/events.pyt after_parent_attach s c C s d S( sÖ Called for each unit of 'column info' retrieved when
a :class:`.Table` is being reflected.
The dictionary of column information as returned by the
dialect is passed, and can be modified. The dictionary
is that returned in each element of the list returned
by :meth:`.reflection.Inspector.get_columns`.
The event is called before any action is taken against
this dictionary, and the contents can be modified.
The :class:`.Column` specific arguments ``info``, ``key``,
and ``quote`` can also be added to the dictionary and
will be passed to the constructor of :class:`.Column`.
Note that this event is only meaningful if either
associated with the :class:`.Table` class across the
board, e.g.::
from sqlalchemy.schema import Table
from sqlalchemy import event
def listen_for_reflect(inspector, table, column_info):
"receive a column_reflect event"
# ...
event.listen(
Table,
'column_reflect',
listen_for_reflect)
...or with a specific :class:`.Table` instance using
the ``listeners`` argument::
def listen_for_reflect(inspector, table, column_info):
"receive a column_reflect event"
# ...
t = Table(
'sometable',
autoload=True,
listeners=[
('column_reflect', listen_for_reflect)
])
This because the reflection process initiated by ``autoload=True``
completes within the scope of the constructor for :class:`.Table`.
N( ( R t inspectort tablet column_info( ( sF /home/tvault/.virtenv/lib/python2.7/site-packages/sqlalchemy/events.pyt column_reflect® s (
t __name__t
__module__t __doc__t _target_class_docR t _dispatch_targetR
R R R R R R ( ( ( sF /home/tvault/.virtenv/lib/python2.7/site-packages/sqlalchemy/events.pyR s 9 t
PoolEventsc B sh e Z d Z d Z e Z e d Z d Z d Z d Z
d Z d Z d Z
d Z RS(
sh Available events for :class:`.Pool`.
The methods here define the name of an event as well
as the names of members that are passed to listener
functions.
e.g.::
from sqlalchemy import event
def my_on_checkout(dbapi_conn, connection_rec, connection_proxy):
"handle an on checkout event"
event.listen(Pool, 'checkout', my_on_checkout)
In addition to accepting the :class:`.Pool` class and
:class:`.Pool` instances, :class:`.PoolEvents` also accepts
:class:`.Engine` objects and the :class:`.Engine` class as
targets, which will be resolved to the ``.pool`` attribute of the
given engine or the :class:`.Pool` class::
engine = create_engine("postgresql://scott:tiger@localhost/test")
# will associate with engine.pool
event.listen(engine, 'checkout', my_on_checkout)
t SomeEngineOrPoolc C sV t | t r8 t | t r" t St | t rR | Sn t | t rN | j S| Sd S( N( t
isinstancet typet
issubclassR R t pool( t clsR
( ( sF /home/tvault/.virtenv/lib/python2.7/site-packages/sqlalchemy/events.pyt _accept_with s c C s d S( sÒ Called at the moment a particular DBAPI connection is first
created for a given :class:`.Pool`.
This event allows one to capture the point directly after which
the DBAPI module-level ``.connect()`` method has been used in order
to produce a new DBAPI connection.
:param dbapi_connection: a DBAPI connection.
:param connection_record: the :class:`._ConnectionRecord` managing the
DBAPI connection.
N( ( R t dbapi_connectiont connection_record( ( sF /home/tvault/.virtenv/lib/python2.7/site-packages/sqlalchemy/events.pyt connect
s c C s d S( s± Called exactly once for the first time a DBAPI connection is
checked out from a particular :class:`.Pool`.
The rationale for :meth:`.PoolEvents.first_connect` is to determine
information about a particular series of database connections based
on the settings used for all connections. Since a particular
:class:`.Pool` refers to a single "creator" function (which in terms
of a :class:`.Engine` refers to the URL and connection options used),
it is typically valid to make observations about a single connection
that can be safely assumed to be valid about all subsequent
connections, such as the database version, the server and client
encoding settings, collation settings, and many others.
:param dbapi_connection: a DBAPI connection.
:param connection_record: the :class:`._ConnectionRecord` managing the
DBAPI connection.
N( ( R R% R&