diff options
Diffstat (limited to 'lib/sqlalchemy/schema.py')
| -rw-r--r-- | lib/sqlalchemy/schema.py | 127 |
1 files changed, 45 insertions, 82 deletions
diff --git a/lib/sqlalchemy/schema.py b/lib/sqlalchemy/schema.py index 5b5983858..fdc961619 100644 --- a/lib/sqlalchemy/schema.py +++ b/lib/sqlalchemy/schema.py @@ -31,6 +31,7 @@ as components in SQL expressions. import re, inspect from sqlalchemy import exc, util, dialects from sqlalchemy.sql import expression, visitors +from sqlalchemy import event URL = None @@ -81,6 +82,20 @@ def _get_table_key(name, schema): else: return schema + "." + name +class DDLEvents(event.Events): + def on_before_create(self, target, connection, **kw): + pass + + def on_after_create(self, target, connection, **kw): + pass + + def on_before_drop(self, target, connection, **kw): + pass + + def on_after_drop(self, target, connection, **kw): + pass + + class Table(SchemaItem, expression.TableClause): """Represent a table in a database. @@ -174,8 +189,7 @@ class Table(SchemaItem, expression.TableClause): __visit_name__ = 'table' - ddl_events = ('before-create', 'after-create', - 'before-drop', 'after-drop') + dispatch = event.dispatcher(DDLEvents) def __new__(cls, *args, **kw): if not args: @@ -227,7 +241,6 @@ class Table(SchemaItem, expression.TableClause): self._set_primary_key(PrimaryKeyConstraint()) self._foreign_keys = util.OrderedSet() self._extra_dependencies = set() - self.ddl_listeners = util.defaultdict(list) self.kwargs = {} if self.schema is not None: self.fullname = "%s.%s" % (self.schema, self.name) @@ -371,37 +384,18 @@ class Table(SchemaItem, expression.TableClause): constraint._set_parent(self) - def append_ddl_listener(self, event, listener): + def append_ddl_listener(self, event_name, listener): """Append a DDL event listener to this ``Table``. - - The ``listener`` callable will be triggered when this ``Table`` is - created or dropped, either directly before or after the DDL is issued - to the database. The listener may modify the Table, but may not abort - the event itself. - :param event: - One of ``Table.ddl_events``; e.g. 'before-create', 'after-create', - 'before-drop' or 'after-drop'. - - :param listener: - A callable, invoked with three positional arguments: - - :event: - The event currently being handled - - :target: - The ``Table`` object being created or dropped - - :bind: - The ``Connection`` bueing used for DDL execution. - - Listeners are added to the Table's ``ddl_listeners`` attribute. + Deprecated. See :class:`.DDLEvents`. """ - - if event not in self.ddl_events: - raise LookupError(event) - self.ddl_listeners[event].append(listener) + + def adapt_listener(target, connection, **kw): + listener(event_name, target, connection, **kw) + + event.listen(adapt_listener, + "on_" + event_name.replace('-', '_'), self) def _set_parent(self, metadata): metadata.tables[_get_table_key(self.name, self.schema)] = self @@ -1835,8 +1829,7 @@ class MetaData(SchemaItem): __visit_name__ = 'metadata' - ddl_events = ('before-create', 'after-create', - 'before-drop', 'after-drop') + dispatch = event.dispatcher(DDLEvents) def __init__(self, bind=None, reflect=False): """Create a new MetaData object. @@ -1856,7 +1849,6 @@ class MetaData(SchemaItem): self.tables = {} self.bind = bind self.metadata = self - self.ddl_listeners = util.defaultdict(list) if reflect: if not bind: raise exc.ArgumentError( @@ -1993,44 +1985,17 @@ class MetaData(SchemaItem): for name in load: Table(name, self, **reflect_opts) - def append_ddl_listener(self, event, listener): + def append_ddl_listener(self, event_name, listener): """Append a DDL event listener to this ``MetaData``. - The ``listener`` callable will be triggered when this ``MetaData`` is - involved in DDL creates or drops, and will be invoked either before - all Table-related actions or after. - - :param event: - One of ``MetaData.ddl_events``; 'before-create', 'after-create', - 'before-drop' or 'after-drop'. - - :param listener: - A callable, invoked with three positional arguments: - - :event: - The event currently being handled - - :target: - The ``MetaData`` object being operated upon - - :bind: - The ``Connection`` bueing used for DDL execution. - - Listeners are added to the MetaData's ``ddl_listeners`` attribute. - - Note: MetaData listeners are invoked even when ``Tables`` are created - in isolation. This may change in a future release. I.e.:: - - # triggers all MetaData and Table listeners: - metadata.create_all() - - # triggers MetaData listeners too: - some.table.create() + Deprecated. See :class:`.DDLEvents`. """ - if event not in self.ddl_events: - raise LookupError(event) - self.ddl_listeners[event].append(listener) + def adapt_listener(target, connection, **kw): + listener(event, target, connection, **kw) + + event.listen(adapt_listener, + "on_" + event_name.replace('-', '_'), self) def create_all(self, bind=None, tables=None, checkfirst=True): """Create all tables stored in this metadata. @@ -2194,7 +2159,7 @@ class DDLElement(expression.Executable, expression.ClauseElement): bind.engine.logger.info( "DDL execution skipped, criteria not met.") - def execute_at(self, event, target): + def execute_at(self, event_name, target): """Link execution of this DDL to the DDL lifecycle of a SchemaItem. Links this ``DDLElement`` to a ``Table`` or ``MetaData`` instance, @@ -2203,9 +2168,10 @@ class DDLElement(expression.Executable, expression.ClauseElement): context as the Table create/drop itself. The ``.bind`` property of this statement is ignored. - :param event: - One of the events defined in the schema item's ``.ddl_events``; - e.g. 'before-create', 'after-create', 'before-drop' or 'after-drop' + :param event_name: + Name of an event from :class:`.DDLEvents`. e.g.: + 'on_before_create', 'on_after_create', 'on_before_drop', + 'on_after_drop'. :param target: The Table or MetaData instance for which this DDLElement will @@ -2220,16 +2186,12 @@ class DDLElement(expression.Executable, expression.ClauseElement): any DDL set to ``execute_at`` that Table's MetaData. This may change in a future release. """ - - if not hasattr(target, 'ddl_listeners'): - raise exc.ArgumentError( - "%s does not support DDL events" % type(target).__name__) - if event not in target.ddl_events: - raise exc.ArgumentError( - "Unknown event, expected one of (%s), got '%r'" % - (', '.join(target.ddl_events), event)) - target.ddl_listeners[event].append(self) - return self + + event_name = "on_" + event_name.replace('-', '_') + def call_event(target, connection, **kw): + self(event_name, target, connection, **kw) + + event.listen(call_event, event_name, target) @expression._generative def against(self, target): @@ -2346,7 +2308,8 @@ class DDL(DDLElement): :event: The name of the event that has triggered this DDL, such as - 'after-create' Will be None if the DDL is executed explicitly. + 'on_after_create' Will be None if the DDL is executed + explicitly. :target: The ``Table`` or ``MetaData`` object which is the target of |