o èã¤gˆGã@s®ddlmZddlmZddlmZddlmZddlmZerJddl m Z dd l m Z dd l m Z dd l m Z dd lmZdd lmZddlmZGdd„dejeƒZdS)é)Ú annotations)ÚAny)Ú TYPE_CHECKINGé)ÚSchemaEventTargeté)Úevent)ÚColumn)Ú Constraint)Ú SchemaItem)ÚTable)Ú Connection)ÚReflectedColumn)Ú Inspectorc@sheZdZdZdZeZd(d d „Zd(d d„Zd(dd„Z d(dd„Z d)dd„Z d)dd„Z d*dd„Z d+d%d&„Zd'S),Ú 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`, etc. **Create / Drop Events** Events emitted when CREATE and DROP commands are emitted to the database. The event hooks in this category include :meth:`.DDLEvents.before_create`, :meth:`.DDLEvents.after_create`, :meth:`.DDLEvents.before_drop`, and :meth:`.DDLEvents.after_drop`. These events are emitted when using schema-level methods such as :meth:`.MetaData.create_all` and :meth:`.MetaData.drop_all`. Per-object create/drop methods such as :meth:`.Table.create`, :meth:`.Table.drop`, :meth:`.Index.create` are also included, as well as dialect-specific methods such as :meth:`_postgresql.ENUM.create`. .. versionadded:: 2.0 :class:`.DDLEvents` event hooks now take place for non-table objects including constraints, indexes, and dialect-specific schema types. Event hooks may be attached directly to a :class:`_schema.Table` object or to a :class:`_schema.MetaData` collection, as well as to any :class:`.SchemaItem` class or object that can be individually created and dropped using a distinct SQL command. Such classes include :class:`.Index`, :class:`.Sequence`, and dialect-specific classes such as :class:`_postgresql.ENUM`. Example using the :meth:`.DDLEvents.after_create` event, where a custom event hook will emit an ``ALTER TABLE`` command on the current connection, after ``CREATE TABLE`` is emitted:: from sqlalchemy import create_engine from sqlalchemy import event from sqlalchemy import Table, Column, Metadata, Integer m = MetaData() some_table = Table("some_table", m, Column("data", Integer)) @event.listens_for(some_table, "after_create") def after_create(target, connection, **kw): connection.execute( text("ALTER TABLE %s SET name=foo_%s" % (target.name, target.name)) ) some_engine = create_engine("postgresql://scott:tiger@host/test") # will emit "CREATE TABLE some_table" as well as the above # "ALTER TABLE" statement afterwards m.create_all(some_engine) Constraint objects such as :class:`.ForeignKeyConstraint`, :class:`.UniqueConstraint`, :class:`.CheckConstraint` may also be subscribed to these events, however they will **not** normally produce events as these objects are usually rendered inline within an enclosing ``CREATE TABLE`` statement and implicitly dropped from a ``DROP TABLE`` statement. For the :class:`.Index` construct, the event hook will be emitted for ``CREATE INDEX``, however SQLAlchemy does not normally emit ``DROP INDEX`` when dropping tables as this is again implicit within the ``DROP TABLE`` statement. .. versionadded:: 2.0 Support for :class:`.SchemaItem` objects for create/drop events was expanded from its previous support for :class:`.MetaData` and :class:`.Table` to also include :class:`.Constraint` and all subclasses, :class:`.Index`, :class:`.Sequence` and some type-related constructs such as :class:`_postgresql.ENUM`. .. note:: These event hooks are only emitted within the scope of SQLAlchemy's create/drop methods; they are not necessarily supported by tools such as `alembic `_. **Attachment Events** Attachment events are 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. These events include :meth:`.DDLEvents.before_parent_attach` and :meth:`.DDLEvents.after_parent_attach`. **Reflection Events** The :meth:`.DDLEvents.column_reflect` event is used to intercept and modify the in-Python definition of database columns when :term:`reflection` of database tables proceeds. **Use with Generic DDL** DDL events integrate closely with the :class:`.DDL` class and the :class:`.ExecutableDDLElement` 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"), ) **Event Propagation to MetaData Copies** 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 metadata = MetaData() some_table = Table("some_table", metadata, Column("data", Integer)) event.listen( some_table, "after_create", DDL("ALTER TABLE %(table)s SET name=foo_%(table)s"), propagate=True, ) new_metadata = MetaData() new_table = some_table.to_metadata(new_metadata) The above :class:`.DDL` object will be associated with the :meth:`.DDLEvents.after_create` event for both the ``some_table`` and the ``new_table`` :class:`.Table` objects. .. seealso:: :ref:`event_toplevel` :class:`.ExecutableDDLElement` :class:`.DDL` :ref:`schema_ddl_sequences` ÚSomeSchemaClassOrObjectÚtargetrÚ connectionr ÚkwrÚreturnÚNonecKódS)a¾Called before CREATE statements are emitted. :param target: the :class:`.SchemaObject`, such as a :class:`_schema.MetaData` or :class:`_schema.Table` but also including all create/drop objects such as :class:`.Index`, :class:`.Sequence`, etc., object which is the target of the event. .. versionadded:: 2.0 Support for all :class:`.SchemaItem` objects was added. :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. N©©ÚselfrrrrrúW/var/www/html/ecg_monitoring/venv/lib/python3.10/site-packages/sqlalchemy/sql/events.pyÚ before_create³ózDDLEvents.before_createcKr)a¥Called after CREATE statements are emitted. :param target: the :class:`.SchemaObject`, such as a :class:`_schema.MetaData` or :class:`_schema.Table` but also including all create/drop objects such as :class:`.Index`, :class:`.Sequence`, etc., object which is the target of the event. .. versionadded:: 2.0 Support for all :class:`.SchemaItem` objects was added. :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. NrrrrrÚ after_create×rzDDLEvents.after_createcKr)a Called before DROP statements are emitted. :param target: the :class:`.SchemaObject`, such as a :class:`_schema.MetaData` or :class:`_schema.Table` but also including all create/drop objects such as :class:`.Index`, :class:`.Sequence`, etc., object which is the target of the event. .. versionadded:: 2.0 Support for all :class:`.SchemaItem` objects was added. :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. NrrrrrÚ before_dropörzDDLEvents.before_dropcKr)a¡Called after DROP statements are emitted. :param target: the :class:`.SchemaObject`, such as a :class:`_schema.MetaData` or :class:`_schema.Table` but also including all create/drop objects such as :class:`.Index`, :class:`.Sequence`, etc., object which is the target of the event. .. versionadded:: 2.0 Support for all :class:`.SchemaItem` objects was added. :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. NrrrrrÚ after_droprzDDLEvents.after_dropÚparentr cCr)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©rrr!rrrÚbefore_parent_attach4rzDDLEvents.before_parent_attachcCr)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. Nrr"rrrÚafter_parent_attachErzDDLEvents.after_parent_attachÚconstr Úcolú Column[Any]cCr)zUinternal event hook used for primary key naming convention updates. Nr)rr%r&rrrÚ'_sa_event_column_added_to_pk_constraintVrz1DDLEvents._sa_event_column_added_to_pk_constraintÚ inspectorrÚtabler Ú column_inforcCr)aùCalled 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)rr)r*r+rrrÚcolumn_reflect^rzDDLEvents.column_reflectN)rrrr rrrr)rrr!r rr)r%r r&r'rr)r)rr*r r+rrr)Ú__name__Ú __module__Ú __qualname__Ú__doc__Ú_target_class_docrÚ_dispatch_targetrrrr r#r$r(r,rrrrrs  $     rN)Ú __future__rÚtypingrrÚbaserÚrÚschemar r r r Ú engine.baser Úengine.interfacesrÚengine.reflectionrÚEventsrrrrrÚs