def item_exists(item_type, item_id, session):
"""Check if the instance with type 'item_type' and id 'item_id'
exists in the database. Returns True if exists else False
:param item_type: The @type of the instance
:type item_type: str
:param item_id: The id of the instance in the database
:type item_id: str
:param session: sqlalchemy scoped session
"""
database_class = get_database_class(item_type)
return session.query(database_class.id).filter_by(id=item_id).scalar() is not None
def insert_single(object_: Dict[str, Any], session: scoped_session) -> Any:
"""Insert instance of classes with single objects.
:param object_: object to be inserted
:param session: sqlalchemy scoped session
:return:
Raises:
ClassNotFound: If `type_` does not represt a valid/defined RDFClass.
Instance: If an Instance of type `type_` already exists.
"""
type_ = object_["@type"]
database_class = get_database_class(type_)
try:
session.query(database_class).all()[-1]
except (NoResultFound, IndexError, ValueError):
return insert(object_, session=session)
raise InstanceExists(type_)