+h3FddlmZddlmZGddejZy))SchemaEventTarget)eventcHeZdZdZdZeZdZdZdZ dZ dZ dZ d Z d Zy ) DDLEventsa Define event listeners for schema objects, that is, :class:`.SchemaItem` and other :class:`.SchemaEventTarget` subclasses, including :class:`_schema.MetaData`, :class:`_schema.Table`, :class:`_schema.Column`. :class:`_schema.MetaData` and :class:`_schema.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:`_schema.Column` is associated with its :class:`_schema.Table`, when a :class:`_schema.ForeignKeyConstraint` is associated with a :class:`_schema.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(text( "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. For all :class:`.DDLEvent` events, the ``propagate=True`` keyword argument will ensure that a given event handler is propagated to copies of the object, which are made when using the :meth:`_schema.Table.to_metadata` method:: from sqlalchemy import DDL event.listen( some_table, "after_create", DDL("ALTER TABLE %(table)s SET name=foo_%(table)s"), propagate=True ) new_table = some_table.to_metadata(new_metadata) The above :class:`.DDL` object will also be associated with the :class:`_schema.Table` object represented by ``new_table``. .. seealso:: :ref:`event_toplevel` :class:`.DDLElement` :class:`.DDL` :ref:`schema_ddl_sequences` SomeSchemaClassOrObjectc y)aCalled before CREATE statements are emitted. :param target: the :class:`_schema.MetaData` or :class:`_schema.Table` object which is the target of the event. :param connection: the :class:`_engine.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. :func:`.event.listen` accepts the ``propagate=True`` modifier for this event; 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:`_schema.Table.to_metadata` is used. :func:`.event.listen` accepts the ``insert=True`` modifier for this event; when True, the listener function will be prepended to the internal list of events upon discovery, and execute before registered listener functions that do not pass this argument. Nselftarget connectionkws H/var/www/html/venv/lib/python3.12/site-packages/sqlalchemy/sql/events.py before_createzDDLEvents.before_create^c y)aCalled after CREATE statements are emitted. :param target: the :class:`_schema.MetaData` or :class:`_schema.Table` object which is the target of the event. :param connection: the :class:`_engine.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. :func:`.event.listen` also accepts the ``propagate=True`` modifier for this event; 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:`_schema.Table.to_metadata` is used. Nr r s r after_createzDDLEvents.after_createyrrc y)aCalled before DROP statements are emitted. :param target: the :class:`_schema.MetaData` or :class:`_schema.Table` object which is the target of the event. :param connection: the :class:`_engine.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. :func:`.event.listen` also accepts the ``propagate=True`` modifier for this event; 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:`_schema.Table.to_metadata` is used. Nr r s r before_dropzDDLEvents.before_droprrc y)aCalled after DROP statements are emitted. :param target: the :class:`_schema.MetaData` or :class:`_schema.Table` object which is the target of the event. :param connection: the :class:`_engine.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. :func:`.event.listen` also accepts the ``propagate=True`` modifier for this event; 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:`_schema.Table.to_metadata` is used. Nr r s r after_dropzDDLEvents.after_droprrcy)a 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 the ``propagate=True`` modifier for this event; 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:`_schema.Table.to_metadata` is used. Nr r r parents rbefore_parent_attachzDDLEvents.before_parent_attachrrcy)a 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 the ``propagate=True`` modifier for this event; 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:`_schema.Table.to_metadata` is used. Nr rs rafter_parent_attachzDDLEvents.after_parent_attachrrcy)zUinternal event hook used for primary key naming convention updates. Nr )r constcols r'_sa_event_column_added_to_pk_constraintz1DDLEvents._sa_event_column_added_to_pk_constraintrrcy)aCalled for each unit of 'column info' retrieved when a :class:`_schema.Table` is being reflected. This event is most easily used by applying it to a specific :class:`_schema.MetaData` instance, where it will take effect for all :class:`_schema.Table` objects within that :class:`_schema.MetaData` that undergo reflection:: metadata = MetaData() @event.listens_for(metadata, 'column_reflect') def receive_column_reflect(inspector, table, column_info): # receives for all Table objects that are reflected # under this MetaData # will use the above event hook my_table = Table("my_table", metadata, autoload_with=some_engine) .. versionadded:: 1.4.0b2 The :meth:`_events.DDLEvents.column_reflect` hook may now be applied to a :class:`_schema.MetaData` object as well as the :class:`_schema.MetaData` class itself where it will take place for all :class:`_schema.Table` objects associated with the targeted :class:`_schema.MetaData`. It may also be applied to the :class:`_schema.Table` class across the board:: from sqlalchemy import Table @event.listens_for(Table, 'column_reflect') def receive_column_reflect(inspector, table, column_info): # receives for all Table objects that are reflected It can also be applied to a specific :class:`_schema.Table` at the point that one is being reflected using the :paramref:`_schema.Table.listeners` parameter:: t1 = Table( "my_table", autoload_with=some_engine, listeners=[ ('column_reflect', receive_column_reflect) ] ) 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`: * ``name`` - the column's name, is applied to the :paramref:`_schema.Column.name` parameter * ``type`` - the type of this column, which should be an instance of :class:`~sqlalchemy.types.TypeEngine`, is applied to the :paramref:`_schema.Column.type` parameter * ``nullable`` - boolean flag if the column is NULL or NOT NULL, is applied to the :paramref:`_schema.Column.nullable` parameter * ``default`` - the column's server default value. This is normally specified as a plain string SQL expression, however the event can pass a :class:`.FetchedValue`, :class:`.DefaultClause`, or :func:`_expression.text` object as well. Is applied to the :paramref:`_schema.Column.server_default` parameter The event is called before any action is taken against this dictionary, and the contents can be modified; the following additional keys may be added to the dictionary to further modify how the :class:`_schema.Column` is constructed: * ``key`` - the string key that will be used to access this :class:`_schema.Column` in the ``.c`` collection; will be applied to the :paramref:`_schema.Column.key` parameter. Is also used for ORM mapping. See the section :ref:`mapper_automated_reflection_schemes` for an example. * ``quote`` - force or un-force quoting on the column name; is applied to the :paramref:`_schema.Column.quote` parameter. * ``info`` - a dictionary of arbitrary data to follow along with the :class:`_schema.Column`, is applied to the :paramref:`_schema.Column.info` parameter. :func:`.event.listen` also accepts the ``propagate=True`` modifier for this event; 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:`_schema.Table.to_metadata` is used. .. seealso:: :ref:`mapper_automated_reflection_schemes` - in the ORM mapping documentation :ref:`automap_intercepting_columns` - in the :ref:`automap_toplevel` documentation :ref:`metadata_reflection_dbagnostic_types` - in the :ref:`metadata_reflection_toplevel` documentation Nr )r inspectortable column_infos rcolumn_reflectzDDLEvents.column_reflectrrN)__name__ __module__ __qualname____doc___target_class_docr_dispatch_targetrrrrrrr#r(r rrrr s@L\2( 6 , , ,     i rrN)baserrEventsrr rrr2s$|  | r