Python 手动插入联接表继承模型的测试数据
我在SQLAlchemy的助手类中有一个get_或_create方法,但会话从不从查询中返回任何数据,因此总是尝试创建新行,即使数据库中存在相同的数据(然后抛出一个Python 手动插入联接表继承模型的测试数据,python,sqlalchemy,Python,Sqlalchemy,我在SQLAlchemy的助手类中有一个get_或_create方法,但会话从不从查询中返回任何数据,因此总是尝试创建新行,即使数据库中存在相同的数据(然后抛出一个唯一CONSTRANT错误) 通过create方法单独添加数据确实可以成功地工作,并且数据会持久化到数据库中。在get\u或\u create()方法中,实例总是None,因此试图再次将数据添加到数据库中 下面的代码是来自完整应用程序的一个片段,应该足以说明问题 models.py: from sqlalchemy import Co
唯一CONSTRANT
错误)
通过create方法单独添加数据确实可以成功地工作,并且数据会持久化到数据库中。在get\u或\u create()
方法中,实例总是None
,因此试图再次将数据添加到数据库中
下面的代码是来自完整应用程序的一个片段,应该足以说明问题
models.py
:
from sqlalchemy import Column, Integer, String, ForeignKey, Float, Enum
from sqlalchemy.ext.declarative import declarative_base
import enum
Base = declarative_base()
class DepositStatus(enum.Enum):
not_yet_paid = 1
paid = 2
to_be_refunded = 3
deposit_kept = 4
refunded = 5
class RiderStatus(enum.Enum):
not_yet_started = 1
active = 2
finished = 3
scratched = 4
class RiderCategories(enum.Enum):
solo = 1
pair = 2
class RiderGenders(enum.Enum):
male = 1
female = 2
class TrackerLocations(Base):
__tablename__ = 'tracker_locations'
id = Column('id', Integer, primary_key=True)
types = Column(String)
__mapper_args__ = {
'polymorphic_on': types
}
class Riders(TrackerLocations):
__tablename__ = 'riders'
id = Column(Integer, ForeignKey('tracker_locations.id'), primary_key=True,
autoincrement=True)
first_name = Column('first_name', String)
last_name = Column('last_name', String)
cap_number = Column('cap_number', String)
category = Column('category', Enum(RiderCategories))
status = Column('status', Enum(RiderStatus))
gender = Column('gender', Enum(RiderGenders))
deposit_status = Column('deposit_status', Enum(DepositStatus))
deposit_amount = Column('deposit_amount', Float)
email = Column('email', String)
__mapper_args__ = {
'polymorphic_identity': 'riders'
}
from sqlalchemy.orm import sessionmaker, scoped_session
from sqlalchemy import create_engine
from models import Base
class DB(object):
"""
To be used to interact with SQLAlchemy's ORM.
"""
def __init__(self, db_uri):
self.engine = create_engine(db_uri)
Base.metadata.create_all(self.engine)
self._session = scoped_session(sessionmaker(bind=self.engine))
def close(self):
self.session.close()
def rollback(self):
self.session.rollback()
@property
def session(self):
return self._session()
def get_or_create(self, model, commit=True, **kwargs):
instance = self.session.query(model).filter_by(**kwargs).first()
if instance:
return instance, False
else:
instance = self.create(model, commit=commit, **kwargs)
return instance, True
def create(self, model, commit=True, **kwargs):
instance = model(**kwargs)
self.session.add(instance)
if commit:
self.session.commit()
return instance
db.py
:
from sqlalchemy import Column, Integer, String, ForeignKey, Float, Enum
from sqlalchemy.ext.declarative import declarative_base
import enum
Base = declarative_base()
class DepositStatus(enum.Enum):
not_yet_paid = 1
paid = 2
to_be_refunded = 3
deposit_kept = 4
refunded = 5
class RiderStatus(enum.Enum):
not_yet_started = 1
active = 2
finished = 3
scratched = 4
class RiderCategories(enum.Enum):
solo = 1
pair = 2
class RiderGenders(enum.Enum):
male = 1
female = 2
class TrackerLocations(Base):
__tablename__ = 'tracker_locations'
id = Column('id', Integer, primary_key=True)
types = Column(String)
__mapper_args__ = {
'polymorphic_on': types
}
class Riders(TrackerLocations):
__tablename__ = 'riders'
id = Column(Integer, ForeignKey('tracker_locations.id'), primary_key=True,
autoincrement=True)
first_name = Column('first_name', String)
last_name = Column('last_name', String)
cap_number = Column('cap_number', String)
category = Column('category', Enum(RiderCategories))
status = Column('status', Enum(RiderStatus))
gender = Column('gender', Enum(RiderGenders))
deposit_status = Column('deposit_status', Enum(DepositStatus))
deposit_amount = Column('deposit_amount', Float)
email = Column('email', String)
__mapper_args__ = {
'polymorphic_identity': 'riders'
}
from sqlalchemy.orm import sessionmaker, scoped_session
from sqlalchemy import create_engine
from models import Base
class DB(object):
"""
To be used to interact with SQLAlchemy's ORM.
"""
def __init__(self, db_uri):
self.engine = create_engine(db_uri)
Base.metadata.create_all(self.engine)
self._session = scoped_session(sessionmaker(bind=self.engine))
def close(self):
self.session.close()
def rollback(self):
self.session.rollback()
@property
def session(self):
return self._session()
def get_or_create(self, model, commit=True, **kwargs):
instance = self.session.query(model).filter_by(**kwargs).first()
if instance:
return instance, False
else:
instance = self.create(model, commit=commit, **kwargs)
return instance, True
def create(self, model, commit=True, **kwargs):
instance = model(**kwargs)
self.session.add(instance)
if commit:
self.session.commit()
return instance
tests.py:
import os
import sqlite3
from tempfile import mkdtemp
from unittest import TestCase
from models import Riders
from db import DB
class TestDBInteractions(TestCase):
@classmethod
def setUpClass(cls):
cls.temp_ = mkdtemp()
cls.temp_db = os.path.join(cls.temp_, 'test_db.db')
def setUp(self):
self.db_uri = 'sqlite:///' + self.temp_db
self.db = DB(self.db_uri)
self.conn = sqlite3.connect(self.temp_db)
self.cur = self.conn.cursor()
def tearDown(self):
self.db.close()
def test_get_or_create(self):
test_data = {
'id': 1,
'first_name': 'Bobby',
'last_name': 'Hill',
'cap_number': '123',
'category': 'solo',
'status': 'finished',
'gender': 'male',
'deposit_status': 'paid',
'deposit_amount': 123.1,
'email': 'hello@bob.com'
}
params = tuple(test_data.values())
query = "INSERT INTO riders VALUES (?,?,?,?,?,?,?,?,?,?)"
self.cur.execute(query, params)
# # sqlite doesn't allow multiple write connections to the same DB, so close this connection
self.conn.commit()
self.conn.close()
self.db1 = DB(db_uri=self.db_uri)
response = self.db1.get_or_create(Riders, **{'id': 1})
print(response)
使用SQLA,您可以很好地忘记甚至有两个表在使用
您的测试设置不会将任何数据插入到跟踪器\u位置
,如果您实例化了骑手的一个实例并通过ORM插入数据,则会出现这种情况
以下是SQLA生成的查询的连接部分:
FROM tracker_locations JOIN riders ON tracker_locations.id = riders.id
在您的测试数据集中,tracker\u locations
中没有行,因此连接条件tracker\u locations.id=riders.id
不会计算为true
因此,如果您还将一些测试数据包括在tracker\u locations
表中,它将起作用:
tracker_locations_test_data = {'id': 1, 'type': 'riders'}
self.cur.execute(
'INSERT INTO tracker_locations VALUES (?,?)',
tuple(tracker_locations_test_data.values()))
仅使用sqlite3
手动将数据加载到riders
表中,不足以尊重riders
模型从TrackerLocations
模型中的“联合继承”。您还必须将正确的数据填充到sqlalchemy的跟踪器位置
,以便能够使用模型
中的信息并进行正确的查找
使用:
对于测试,它应该可以工作。太棒了!非常感谢。关于查看SQLA执行的SQL查询,学到了很好的一课。我已经在这个问题上纠缠太久了,我应该早点转向stackoverflow。再次感谢。是的,echo=True
可以节省时间!您好,非常感谢您的帮助,这是您和Supershot强调的正确方法。由于外部链接和SQL查询的详细信息,仅接受他们的答案。再次感谢