Label is a class within the sqlalchemy.sql.elements module of the SQLAlchemy project.
ColumnElement
is another callable from the sqlalchemy.sql.elements package with code examples.
GINO (project documentation and PyPI package information) is an object-relational mapper (ORM) built on SQLAlchemy that is non-blocking and therefore designed to work properly with asynchronously-run code, for example, an application written with asyncio.
GINO is open sourced under the BSD License.
# loader.py
import types
import warnings
from sqlalchemy import select
from sqlalchemy.schema import Column
from sqlalchemy.sql.elements import Label
from .declarative import Model
class Loader:
@classmethod
def get(cls, value):
from .crud import Alias
if isinstance(value, Loader):
rv = value
elif isinstance(value, type) and issubclass(value, Model):
rv = ModelLoader(value)
elif isinstance(value, Alias):
rv = AliasLoader(value)
elif isinstance(value, Column):
rv = ColumnLoader(value)
elif isinstance(value, Label):
rv = ColumnLoader(value.name)
elif isinstance(value, tuple):
rv = TupleLoader(value)
elif callable(value):
rv = CallableLoader(value)
else:
rv = ValueLoader(value)
return rv
@property
def query(self):
rv = select(self.get_columns())
from_clause = self.get_from()
if from_clause is not None:
rv = rv.select_from(from_clause)
return rv.execution_options(loader=self)
def do_load(self, row, context):
raise NotImplementedError
def get_columns(self):
return []
def get_from(self):
## ... source file continues with no further Label examples...
indico (project website, documentation and sandbox demo) is a Flask-based web app for event management that is powered by SQLAlchemy on the backend. The code for this project is open sourced under the MIT license.
indico / indico / core / marshmallow.py
# marshmallow.py
from __future__ import absolute_import, unicode_literals
from inspect import getmro
from flask_marshmallow import Marshmallow
from flask_marshmallow.sqla import SchemaOpts
from marshmallow import fields, post_dump, post_load, pre_load
from marshmallow_enum import EnumField
from marshmallow_sqlalchemy import ModelConverter
from marshmallow_sqlalchemy import ModelSchema as MSQLAModelSchema
from sqlalchemy.orm import ColumnProperty
from sqlalchemy.sql.elements import Label
from webargs.flaskparser import parser as webargs_flask_parser
from indico.core import signals
from indico.core.db.sqlalchemy import PyIntEnum, UTCDateTime
from indico.web.args import parser as indico_webargs_flask_parser
mm = Marshmallow()
def _is_column_property(prop):
return hasattr(prop, 'columns') and isinstance(prop.columns[0], Label)
class IndicoModelConverter(ModelConverter):
SQLA_TYPE_MAPPING = ModelConverter.SQLA_TYPE_MAPPING.copy()
SQLA_TYPE_MAPPING.update({
UTCDateTime: fields.DateTime,
PyIntEnum: EnumField
})
def _get_field_kwargs_for_property(self, prop):
kwargs = super(IndicoModelConverter, self)._get_field_kwargs_for_property(prop)
if isinstance(prop, ColumnProperty) and hasattr(prop.columns[0].type, 'marshmallow_get_field_kwargs'):
## ... source file continues with no further Label examples...