Python sqlalchemy.DDL Examples

def __init__(
            self, element, on=None, bind=None,
            include_foreign_key_constraints=None):
        """Create a :class:`.CreateTable` construct.

        :param element: a :class:`.Table` that's the subject
         of the CREATE
        :param on: See the description for 'on' in :class:`.DDL`.
        :param bind: See the description for 'bind' in :class:`.DDL`.
        :param include_foreign_key_constraints: optional sequence of
         :class:`.ForeignKeyConstraint` objects that will be included
         inline within the CREATE construct; if omitted, all foreign key
         constraints that do not specify use_alter=True are included.

         .. versionadded:: 1.0.0

        """
        super(CreateTable, self).__init__(element, on=on, bind=bind)
        self.columns = [CreateColumn(column)
                        for column in element.columns
                        ]
        self.include_foreign_key_constraints = include_foreign_key_constraints 

def __init__(
            self, element, on=None, bind=None,
            include_foreign_key_constraints=None):
        """Create a :class:`.CreateTable` construct.

        :param element: a :class:`.Table` that's the subject
         of the CREATE
        :param on: See the description for 'on' in :class:`.DDL`.
        :param bind: See the description for 'bind' in :class:`.DDL`.
        :param include_foreign_key_constraints: optional sequence of
         :class:`.ForeignKeyConstraint` objects that will be included
         inline within the CREATE construct; if omitted, all foreign key
         constraints that do not specify use_alter=True are included.

         .. versionadded:: 1.0.0

        """
        super(CreateTable, self).__init__(element, on=on, bind=bind)
        self.columns = [CreateColumn(column)
                        for column in element.columns
                        ]
        self.include_foreign_key_constraints = include_foreign_key_constraints 

def __init__(
            self, element, on=None, bind=None,
            include_foreign_key_constraints=None):
        """Create a :class:`.CreateTable` construct.

        :param element: a :class:`.Table` that's the subject
         of the CREATE
        :param on: See the description for 'on' in :class:`.DDL`.
        :param bind: See the description for 'bind' in :class:`.DDL`.
        :param include_foreign_key_constraints: optional sequence of
         :class:`.ForeignKeyConstraint` objects that will be included
         inline within the CREATE construct; if omitted, all foreign key
         constraints that do not specify use_alter=True are included.

         .. versionadded:: 1.0.0

        """
        super(CreateTable, self).__init__(element, on=on, bind=bind)
        self.columns = [CreateColumn(column)
                        for column in element.columns
                        ]
        self.include_foreign_key_constraints = include_foreign_key_constraints 

def add_new_photo_to_session(session, *, id, **kwargs):
    """Create a new Photo and update the referenced PhotoAnswer."""
    try:
        answer = (
            session
            .query(PhotoAnswer)
            .filter_by(main_answer=id)
            .one()
        )
    except NoResultFound:
        raise PhotoIdDoesNotExistError(id)
    with session.begin():
        answer.photo = Photo(id=id, **kwargs)
        answer.actual_photo_id = answer.main_answer
    return answer.photo


# sa.event.listen(
#     Photo.__table__,
#     'after_create',
#     sa.DDL(
#         'CREATE TRIGGER t_image BEFORE UPDATE OR DELETE ON photo'
#         ' FOR EACH ROW EXECUTE PROCEDURE lo_manage(image)'
#     ),
# ) 

def __init__(
            self, element, on=None, bind=None,
            include_foreign_key_constraints=None):
        """Create a :class:`.CreateTable` construct.

        :param element: a :class:`.Table` that's the subject
         of the CREATE
        :param on: See the description for 'on' in :class:`.DDL`.
        :param bind: See the description for 'bind' in :class:`.DDL`.
        :param include_foreign_key_constraints: optional sequence of
         :class:`.ForeignKeyConstraint` objects that will be included
         inline within the CREATE construct; if omitted, all foreign key
         constraints that do not specify use_alter=True are included.

         .. versionadded:: 1.0.0

        """
        super(CreateTable, self).__init__(element, on=on, bind=bind)
        self.columns = [CreateColumn(column)
                        for column in element.columns
                        ]
        self.include_foreign_key_constraints = include_foreign_key_constraints 

def define_tables(cls, metadata):
        # the actual function isn't reflected yet
        dv = Table(
            "data_values",
            metadata,
            Column("modulus", Integer, nullable=False),
            Column("data", String(30)),
            Column("q", Integer),
            postgresql_partition_by="range(modulus)",
        )

        # looks like this is reflected prior to #4237
        sa.event.listen(
            dv,
            "after_create",
            sa.DDL(
                "CREATE TABLE data_values_4_10 PARTITION OF data_values "
                "FOR VALUES FROM (4) TO (10)"
            ),
        )

        if testing.against("postgresql >= 11"):
            Index("my_index", dv.c.q) 

def __init__(
        self, element, bind=None, include_foreign_key_constraints=None
    ):
        """Create a :class:`.CreateTable` construct.

        :param element: a :class:`_schema.Table` that's the subject
         of the CREATE
        :param on: See the description for 'on' in :class:`.DDL`.
        :param bind: See the description for 'bind' in :class:`.DDL`.
        :param include_foreign_key_constraints: optional sequence of
         :class:`_schema.ForeignKeyConstraint` objects that will be included
         inline within the CREATE construct; if omitted, all foreign key
         constraints that do not specify use_alter=True are included.

         .. versionadded:: 1.0.0

        """
        super(CreateTable, self).__init__(element, bind=bind)
        self.columns = [CreateColumn(column) for column in element.columns]
        self.include_foreign_key_constraints = include_foreign_key_constraints 

def upgrade():
    conn = op.get_bind()
    func = sa.DDL("""CREATE FUNCTION set_meta_updated()
                      RETURNS TRIGGER
                      LANGUAGE plpgsql
                    AS $$
                    BEGIN
                      NEW.meta_updated := now();
                      RETURN NEW;
                    END;
                    $$;""")
    conn.execute(func)

    for table in updatable_tables:
        trigger_params = {'trigger': ('%s_set_meta_updated' % table), 'table': table}
        trigger = ("""CREATE TRIGGER %(trigger)s
                    BEFORE UPDATE ON %(table)s
                    FOR EACH ROW EXECUTE PROCEDURE set_meta_updated();""" % trigger_params)
        conn.execute(trigger) 

def __init__(
            self, element, on=None, bind=None,
            include_foreign_key_constraints=None):
        """Create a :class:`.CreateTable` construct.

        :param element: a :class:`.Table` that's the subject
         of the CREATE
        :param on: See the description for 'on' in :class:`.DDL`.
        :param bind: See the description for 'bind' in :class:`.DDL`.
        :param include_foreign_key_constraints: optional sequence of
         :class:`.ForeignKeyConstraint` objects that will be included
         inline within the CREATE construct; if omitted, all foreign key
         constraints that do not specify use_alter=True are included.

         .. versionadded:: 1.0.0

        """
        super(CreateTable, self).__init__(element, on=on, bind=bind)
        self.columns = [CreateColumn(column)
                        for column in element.columns
                        ]
        self.include_foreign_key_constraints = include_foreign_key_constraints 

def __init__(
            self, element, on=None, bind=None,
            include_foreign_key_constraints=None):
        """Create a :class:`.CreateTable` construct.

        :param element: a :class:`.Table` that's the subject
         of the CREATE
        :param on: See the description for 'on' in :class:`.DDL`.
        :param bind: See the description for 'bind' in :class:`.DDL`.
        :param include_foreign_key_constraints: optional sequence of
         :class:`.ForeignKeyConstraint` objects that will be included
         inline within the CREATE construct; if omitted, all foreign key
         constraints that do not specify use_alter=True are included.

         .. versionadded:: 1.0.0

        """
        super(CreateTable, self).__init__(element, on=on, bind=bind)
        self.columns = [CreateColumn(column)
                        for column in element.columns
                        ]
        self.include_foreign_key_constraints = include_foreign_key_constraints 

def __init__(self, statement, context=None, bind=None):
        """Create a DDL statement.

        :param statement:
          A string or unicode string to be executed.  Statements will be
          processed with Python's string formatting operator.  See the
          ``context`` argument and the ``execute_at`` method.

          A literal '%' in a statement must be escaped as '%%'.

          SQL bind parameters are not available in DDL statements.

        :param context:
          Optional dictionary, defaults to None.  These values will be
          available for use in string substitutions on the DDL statement.

        :param bind:
          Optional. A :class:`.Connectable`, used by
          default when ``execute()`` is invoked without a bind argument.


        .. seealso::

            :class:`.DDLEvents`

            :ref:`event_toplevel`

        """

        if not isinstance(statement, util.string_types):
            raise exc.ArgumentError(
                "Expected a string or unicode SQL statement, got '%r'"
                % statement
            )

        self.statement = statement
        self.context = context or {}

        self._bind = bind 

def against(self, target):
        """Return a copy of this DDL against a specific schema item."""

        self.target = target 

def define_tables(cls, metadata):
        testtable = Table(
            "testtable",
            metadata,
            Column("id", Integer, primary_key=True),
            Column("data", String(30)),
        )

        # insert data before we create the view
        @sa.event.listens_for(testtable, "after_create")
        def insert_data(target, connection, **kw):
            connection.execute(target.insert(), {"id": 89, "data": "d1"})

        materialized_view = sa.DDL(
            "CREATE MATERIALIZED VIEW test_mview AS " "SELECT * FROM testtable"
        )

        plain_view = sa.DDL(
            "CREATE VIEW test_regview AS " "SELECT * FROM testtable"
        )

        sa.event.listen(testtable, "after_create", plain_view)
        sa.event.listen(testtable, "after_create", materialized_view)
        sa.event.listen(
            testtable,
            "before_drop",
            sa.DDL("DROP MATERIALIZED VIEW test_mview"),
        )
        sa.event.listen(
            testtable, "before_drop", sa.DDL("DROP VIEW test_regview")
        ) 

def test_time_types(self):
        specs = []

        if testing.requires.mysql_fsp.enabled:
            fsps = [None, 0, 5]
        else:
            fsps = [None]

        for type_ in (mysql.TIMESTAMP, mysql.DATETIME, mysql.TIME):
            # MySQL defaults fsp to 0, and if 0 does not report it.
            # we don't actually render 0 right now in DDL but even if we do,
            # it comes back blank
            for fsp in fsps:
                if fsp:
                    specs.append((type_(fsp=fsp), type_(fsp=fsp)))
                else:
                    specs.append((type_(), type_()))

        specs.extend(
            [(TIMESTAMP(), mysql.TIMESTAMP()), (DateTime(), mysql.DATETIME())]
        )

        # note 'timezone' should always be None on both
        self._run_test(specs, ["fsp", "timezone"]) 

def execute(self, bind=None, target=None):
        """Execute this DDL immediately.

        Executes the DDL statement in isolation using the supplied
        :class:`.Connectable` or
        :class:`.Connectable` assigned to the ``.bind``
        property, if not supplied. If the DDL has a conditional ``on``
        criteria, it will be invoked with None as the event.

        :param bind:
          Optional, an ``Engine`` or ``Connection``. If not supplied, a valid
          :class:`.Connectable` must be present in the
          ``.bind`` property.

        :param target:
          Optional, defaults to None.  The target SchemaItem for the
          execute call.  Will be passed to the ``on`` callable if any,
          and may also provide string expansion data for the
          statement. See ``execute_at`` for more information.

        """

        if bind is None:
            bind = _bind_or_error(self)

        if self._should_execute(target, bind):
            return bind.execute(self.against(target))
        else:
            bind.engine.logger.info(
                "DDL execution skipped, criteria not met.") 

def __call__(self, target, bind, **kw):
        """Execute the DDL as a ddl_listener."""

        if self._should_execute(target, bind, **kw):
            return bind.execute(self.against(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,
        executing it when that schema item is created or dropped. The DDL
        statement will be executed using the same Connection and transactional
        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 target:
          The Table or MetaData instance for which this DDLElement will
          be associated with.

        A DDLElement instance can be linked to any number of schema items.

        ``execute_at`` builds on the ``append_ddl_listener`` interface of
        :class:`.MetaData` and :class:`.Table` objects.

        Caveat: Creating or dropping a Table in isolation will also trigger
        any DDL set to ``execute_at`` that Table's MetaData.  This may change
        in a future release.

        """

        def call_event(target, connection, **kw):
            if self._should_execute_deprecated(event_name,
                                               target, connection, **kw):
                return connection.execute(self.against(target))

        event.listen(target, "" + event_name.replace('-', '_'), call_event) 

def __init__(self, element, on=None, bind=None):
        """Create a :class:`.CreateTable` construct.

        :param element: a :class:`.Table` that's the subject
         of the CREATE
        :param on: See the description for 'on' in :class:`.DDL`.
        :param bind: See the description for 'bind' in :class:`.DDL`.

        """
        super(CreateTable, self).__init__(element, on=on, bind=bind)
        self.columns = [CreateColumn(column)
                        for column in element.columns
                        ] 

def against(self, target):
        """Return a copy of this DDL against a specific schema item."""

        self.target = target 

def __call__(self, target, bind, **kw):
        """Execute the DDL as a ddl_listener."""

        if self._should_execute(target, bind, **kw):
            return bind.execute(self.against(target)) 

def load_ddl():
    for script in ('triggers.sql', 'rpmvercmp.sql'):
        with open(os.path.join(get_config('directories.datadir'), script)) as ddl_script:
            ddl = DDL(ddl_script.read())
        listen(Base.metadata, 'after_create', ddl.execute_if(dialect='postgresql')) 

def execute(self, bind=None, target=None):
        """Execute this DDL immediately.

        Executes the DDL statement in isolation using the supplied
        :class:`.Connectable` or
        :class:`.Connectable` assigned to the ``.bind``
        property, if not supplied. If the DDL has a conditional ``on``
        criteria, it will be invoked with None as the event.

        :param bind:
          Optional, an ``Engine`` or ``Connection``. If not supplied, a valid
          :class:`.Connectable` must be present in the
          ``.bind`` property.

        :param target:
          Optional, defaults to None.  The target SchemaItem for the
          execute call.  Will be passed to the ``on`` callable if any,
          and may also provide string expansion data for the
          statement. See ``execute_at`` for more information.

        """

        if bind is None:
            bind = _bind_or_error(self)

        if self._should_execute(target, bind):
            return bind.execute(self.against(target))
        else:
            bind.engine.logger.info(
                        "DDL execution skipped, criteria not met.") 

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,
        executing it when that schema item is created or dropped. The DDL
        statement will be executed using the same Connection and transactional
        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 target:
          The Table or MetaData instance for which this DDLElement will
          be associated with.

        A DDLElement instance can be linked to any number of schema items.

        ``execute_at`` builds on the ``append_ddl_listener`` interface of
        :class:`.MetaData` and :class:`.Table` objects.

        Caveat: Creating or dropping a Table in isolation will also trigger
        any DDL set to ``execute_at`` that Table's MetaData.  This may change
        in a future release.

        """

        def call_event(target, connection, **kw):
            if self._should_execute_deprecated(event_name,
                                    target, connection, **kw):
                return connection.execute(self.against(target))

        event.listen(target, "" + event_name.replace('-', '_'), call_event) 

def against(self, target):
        """Return a copy of this DDL against a specific schema item."""

        self.target = target 

def __call__(self, target, bind, **kw):
        """Execute the DDL as a ddl_listener."""

        if self._should_execute(target, bind, **kw):
            return bind.execute(self.against(target)) 

def __init__(self, element, on=None, bind=None):
        """Create a :class:`.CreateTable` construct.

        :param element: a :class:`.Table` that's the subject
         of the CREATE
        :param on: See the description for 'on' in :class:`.DDL`.
        :param bind: See the description for 'bind' in :class:`.DDL`.

        """
        super(CreateTable, self).__init__(element, on=on, bind=bind)
        self.columns = [CreateColumn(column)
            for column in element.columns
        ] 

def execute(self, bind=None, target=None):
        """Execute this DDL immediately.

        Executes the DDL statement in isolation using the supplied
        :class:`.Connectable` or
        :class:`.Connectable` assigned to the ``.bind``
        property, if not supplied. If the DDL has a conditional ``on``
        criteria, it will be invoked with None as the event.

        :param bind:
          Optional, an ``Engine`` or ``Connection``. If not supplied, a valid
          :class:`.Connectable` must be present in the
          ``.bind`` property.

        :param target:
          Optional, defaults to None.  The target SchemaItem for the
          execute call.  Will be passed to the ``on`` callable if any,
          and may also provide string expansion data for the
          statement. See ``execute_at`` for more information.

        """

        if bind is None:
            bind = _bind_or_error(self)

        if self._should_execute(target, bind):
            return bind.execute(self.against(target))
        else:
            bind.engine.logger.info(
                "DDL execution skipped, criteria not met.") 

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,
        executing it when that schema item is created or dropped. The DDL
        statement will be executed using the same Connection and transactional
        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 target:
          The Table or MetaData instance for which this DDLElement will
          be associated with.

        A DDLElement instance can be linked to any number of schema items.

        ``execute_at`` builds on the ``append_ddl_listener`` interface of
        :class:`.MetaData` and :class:`.Table` objects.

        Caveat: Creating or dropping a Table in isolation will also trigger
        any DDL set to ``execute_at`` that Table's MetaData.  This may change
        in a future release.

        """

        def call_event(target, connection, **kw):
            if self._should_execute_deprecated(event_name,
                                               target, connection, **kw):
                return connection.execute(self.against(target))

        event.listen(target, "" + event_name.replace('-', '_'), call_event) 

def against(self, target):
        """Return a copy of this DDL against a specific schema item."""

        self.target = target 

def __call__(self, target, bind, **kw):
        """Execute the DDL as a ddl_listener."""

        if self._should_execute(target, bind, **kw):
            return bind.execute(self.against(target))