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""" | |
This gist provides several mixins to be used on any number of sqlachemy models | |
1. HasLogMixin, provides a list EntityLog items specific and attached to an instance of the class | |
2. IsActor or IsReceiver mixins that allow the class to be related to an EntityLog item | |
as an actor or receiver | |
The ideal goal is EntityLog items, relatable to specific instances, and queryable by actor/receiver | |
attachable to any number of items with mixins. | |
most likely requires something approximating: | |
http://docs.sqlalchemy.org/en/rel_0_9/_modules/examples/generic_associations/discriminator_on_association.html | |
but I haven't been able to adapt it | |
""" | |
import random | |
from sqlalchemy.ext.declarative import as_declarative, declared_attr | |
from sqlalchemy import create_engine, Integer, Column, String, ForeignKey, Table | |
from sqlalchemy.orm import Session, relationship, backref | |
# from sqlalchemy.ext.associationproxy import association_proxy | |
@as_declarative() | |
class Base(object): | |
@declared_attr | |
def __tablename__(cls): | |
return cls.__name__.lower() | |
id = Column(Integer, primary_key=True) | |
class EntityLog(Base): | |
info = Column(String) | |
actor = relationship("Actor", uselist=False, backref="entity_log_actor") | |
receiver = relationship("Receiver", uselist=False, backref="entity_log_receiver") | |
def __init__(self, **kwargs): | |
if kwargs.get('actor'): | |
self.add_actor(kwargs.pop('actor')) | |
if kwargs.get('receiver'): | |
self.add_receiver(kwargs.pop('receiver')) | |
self.info = str(kwargs) | |
def add_actor(self, mdl): | |
a = Actor() | |
setattr(a, mdl.__tablename__, mdl) | |
setattr(self, 'actor', a) | |
def add_receiver(self, mdl): | |
r = Receiver() | |
setattr(r, mdl.__tablename__, mdl) | |
setattr(self, 'receiver', r) | |
class Actor(Base): | |
entity_log_id = Column(Integer, ForeignKey("entitylog.id")) | |
class Receiver(Base): | |
entity_log_id = Column(Integer, ForeignKey("entitylog.id")) | |
class IsActorMixin(object): | |
@declared_attr | |
def is_actor(cls): | |
actor_assoc = Table( | |
"{}_actor_assoc".format(cls.__tablename__), | |
cls.metadata, | |
Column("actor_id", | |
ForeignKey('actor.id'), | |
primary_key=True), | |
Column("{}_id".format(cls.__tablename__), | |
ForeignKey("{}.id".format(cls.__tablename__)), | |
primary_key=True), | |
extend_existing=True | |
) | |
return relationship("Actor", | |
backref=backref("{}".format(cls.__tablename__), uselist=False), | |
secondary=actor_assoc) | |
class IsReceiverMixin(object): | |
@declared_attr | |
def is_receiver(cls): | |
rec_assoc = Table( | |
"{}_perf_assoc".format(cls.__tablename__), | |
cls.metadata, | |
Column("receiver_id", | |
ForeignKey('receiver.id'), | |
primary_key=True), | |
Column("{}_id".format(cls.__tablename__), | |
ForeignKey("{}.id".format(cls.__tablename__)), | |
primary_key=True), | |
extend_existing=True | |
) | |
return relationship("Receiver", | |
backref=backref("{}".format(cls.__tablename__), uselist=False), | |
secondary=rec_assoc) | |
class HasLogMixin(object): | |
@declared_attr | |
def log(cls): | |
log_assoc = Table( | |
"{}_log".format(cls.__tablename__), | |
cls.metadata, | |
Column("entitylogid", | |
ForeignKey("entitylog.id"), | |
primary_key=True), | |
Column("{}_id".format(cls.__tablename__), | |
ForeignKey("{}.id".format(cls.__tablename__)), | |
primary_key=True), | |
) | |
return relationship("EntityLog", secondary=log_assoc) | |
class ModelOne(HasLogMixin, IsActorMixin, IsReceiverMixin, Base): | |
tag = Column(String) | |
class ModelTwo(HasLogMixin, IsActorMixin, IsReceiverMixin, Base): | |
tag = Column(String) | |
engine = create_engine('sqlite://', echo=True) | |
Base.metadata.drop_all(engine) | |
Base.metadata.create_all(engine) | |
session = Session(engine) | |
a = ModelOne(tag="ONE") | |
b = ModelTwo(tag="Two") | |
c = ModelOne(tag="3") | |
d = ModelTwo(tag="IV") | |
perf_opts = [a, b, c, d] | |
a.log.append(EntityLog(actor=a, receiver=random.choice(perf_opts))) | |
for x in perf_opts: | |
for i in range(5): | |
x.log.append(EntityLog(actor=x, receiver=random.choice(perf_opts))) | |
for i in range(5): | |
x.log.append(EntityLog(actor=random.choice(perf_opts), receiver=x)) | |
session.add_all([a, b, c, d]) | |
session.commit() | |
session.query(Actor).filter_by(modelone=a) | |
# session.query(EntityLog).filter_by(actor=a) | |
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