strategies is a callable within the
sqlalchemy.orm module of the SQLAlchemy project.
are several other callables with code examples from the same
graphene-sqlalchemy (project documentation and PyPI package information) is a SQLAlchemy integration for Graphene, which makes it easier to build GraphQL-based APIs into Python web applications. The package allows you to subclass SQLAlchemy classes and build queries around them with custom code to match the backend queries with the GraphQL-based request queries. The project is provided as open source under the MIT license.
# batching.py import sqlalchemy from promise import dataloader, promise from sqlalchemy.orm import Session, strategies from sqlalchemy.orm.query import QueryContext def get_batch_resolver(relationship_prop): selectin_loader = strategies.SelectInLoader(relationship_prop, (('lazy', 'selectin'),)) class RelationshipLoader(dataloader.DataLoader): cache = False def batch_load_fn(self, parents): # pylint: disable=method-hidden child_mapper = relationship_prop.mapper parent_mapper = relationship_prop.parent session = Session.object_session(parents) for parent in parents: assert session is Session.object_session(parent) assert parent not in session.dirty states = [(sqlalchemy.inspect(parent), True) for parent in parents] query_context = QueryContext(session.query(parent_mapper.entity)) selectin_loader._load_for_path( query_context, parent_mapper._path_registry, states, None, child_mapper, ) ## ... source file continues with no further strategies examples...