sqlalchemy: obtener el objeto estado de la instancia

Question

Este: Intro to object states enumera las cuatro permutaciones de presencia-en-DB/presencia, durante la reunión:

transient, pending, persistent & detached 

¿Hay alguna manera de hacer consultas a un objeto determinado para volver a cuál de las cuatro estados en los que se encuentra el objeto?

Intenté rooting en _sa_instance_state pero no encontré nada relevante.

Gracias!

Answer 1

Mejor uso Inspection API:

from sqlalchemy import inspect 
state = inspect(obj) 

# Booleans 
state.transient 
state.pending 
state.detached 
state.persistent 

Answer 2

[Actualización: Esta respuesta es para las versiones antes de 0.8]

encontrado que es here:

from sqlalchemy.orm import object_session 
from sqlalchemy.orm.util import has_identity 

# transient: 
object_session(obj) is None and not has_identity(obj) 
# pending: 
object_session(obj) is not None and not has_identity(obj) 
# detached: 
object_session(obj) is None and has_identity(obj) 
# persistent: 
object_session(obj) is not None and has_identity(obj) 

Answer 3

otra opción, que enumera todos los objetos en estados particulares dentro de una sesión: http://docs.sqlalchemy.org/en/latest/orm/session.html#session-attributes

# pending objects recently added to the Session 
session.new 

# persistent objects which currently have changes detected 
# (this collection is now created on the fly each time the property is called) 
session.dirty 

# persistent objects that have been marked as deleted via session.delete(obj) 
session.deleted 

# dictionary of all persistent objects, keyed on their 
# identity key 
session.identity_map 

Answer 4

Otra opción es object_state, resintonizando InstanceState:

from sqlalchemy.orm.util import object_state 

state = object_state(obj) 
# here are the four states: 
state.transient # !session & !identity_key 
state.pending # session & !identity_key 
state.persistent # session & identity_key 
state.detached # !session & identity_key 
# and low-level attrs 
state.identity_key 
state.has_identity # bool(identity_key) 
state.session