我最近尝试将代码从Python2.7升级到Python3.4。
在Python 2.7中,这很简单:
class Maatje(CommonColumns):
koppelvoorstellen = db.relationship("Koppelvoorstel",
primaryjoin="or_(Maatje.id == Koppelvoorstel.deelnemerID," \
+ "Maatje.id == Koppelvoorstel.vrijwilligerID)",
cascade="all,delete-orphan")
但是,使用Python 3.4(和mod_wsgi 4.4,从源代码编译而来,与Python3.4相反),当我试图查询Maatje时,在我的Apache 2.4错误日志中出现了一个错误:
[wsgi:error] [pid 6169] sqlalchemy.exc.ProgrammingError:
(mysql.connector.errors.ProgrammingError) 1064 (42000): You have an
error in your SQL syntax; check the manual that corresponds to your
MySQL server version for the right syntax to use near '%(param_1)s =
koppelvoorstel.`vrijwilligerID`' at line 3 [SQL: 'SELECT
koppelvoorstel.id AS koppelvoorstel_id, koppelvoorstel.aangemaakt AS
koppelvoorstel_aangemaakt, koppelvoorstel.gewijzigd AS
koppelvoorstel_gewijzigd, koppelvoorstel.etag AS koppelvoorstel_etag,
koppelvoorstel.`deelnemerID` AS `koppelvoorstel_deelnemerID`,
koppelvoorstel.`vrijwilligerID` AS `koppelvoorstel_vrijwilligerID`,
koppelvoorstel.akkoordvrijwilliger AS
koppelvoorstel_akkoordvrijwilliger, koppelvoorstel.akkoorddeelnemer AS
koppelvoorstel_akkoorddeelnemer,
koppelvoorstel.redenafwijzingvrijwilliger AS
koppelvoorstel_redenafwijzingvrijwilliger,
koppelvoorstel.redenafwijzingdeelnemer AS
koppelvoorstel_redenafwijzingdeelnemer, koppelvoorstel.stopdatum AS
koppelvoorstel_stopdatum, koppelvoorstel.redenstoppenvrijwilliger AS
koppelvoorstel_redenstoppenvrijwilliger,
koppelvoorstel.redenstoppendeelnemer AS
koppelvoorstel_redenstoppendeelnemer \\nFROM koppelvoorstel \\nWHERE %
(param_1)s = koppelvoorstel.`deelnemerID` OR %(param_1)s =
koppelvoorstel.`vrijwilligerID`'] [parameters: {'param_1': 1}]
在我看来,SQL是完全有效的(我假设\\n将成为一个换行符)。我使用phpMyAdmin(不带)尝试了SQL查询,并填充了参数(一个),它理解了查询并得出了有效的结果。
我试过写
primaryjoin
在其他形式中,例如不带字符串、带or和带“|”作为或运算符。还尝试了
in_
-操作员。
我使用Ubuntu 14.04和mod_wsgi 4.4、SQLalchemy 1.0.12和Flask SQLalchemi 2.1。
我正在使用
python3-mysql.connector
(用于MySQL Connector/Python的Ubuntu包)。
如果我删除了其中一个等式比较(不管是哪一个),并且没有使用
or_
-运算符,则它不会抛出错误。但我需要同时使用
或_
-操作员。
2016年3月6日:
现在我把问题隔离了一点。使用python2.7运行以下代码不会产生任何问题:
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
app = Flask(__name__)
app.config['SQLALCHEMY_ECHO'] = True
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql+mysqlconnector://username:password@127.0.0.1/primaryjoindb'
db = SQLAlchemy(app)
class Coupleproposal(db.Model):
__tablename__ = 'coupleproposal'
id = db.Column(db.Integer, primary_key=True)
participantID = db.Column(db.Integer, db.ForeignKey('buddy.id'), nullable = False)
volunteerID = db.Column(db.Integer, db.ForeignKey('buddy.id'), nullable = False)
participant = db.relationship("Buddy", foreign_keys=[participantID])
volunteer = db.relationship("Buddy", foreign_keys=[volunteerID])
__table_args__ = (db.UniqueConstraint('participantID', 'volunteerID', name='_couple_uc'),)
class Buddy(db.Model):
__tablename__ = 'buddy'
id = db.Column(db.Integer, primary_key=True)
coupleproposals = db.relationship("Coupleproposal", \
primaryjoin="(Buddy.id == Coupleproposal.participantID) | (Buddy.id == Coupleproposal.volunteerID)", \
cascade="all,delete-orphan")
db.create_all()
b1 = Buddy()
b2 = Buddy()
db.session.add(b1)
db.session.add(b2)
cp1 = Coupleproposal(participantID=1, volunteerID=1)
db.session.add(cp1)
db.session.commit()
for aBuddy in db.session.query(Buddy).all():
print(aBuddy.id)
print(aBuddy.coupleproposals)
但是使用python3.4运行代码会引发以下错误:
sqlalchemy.exc.ProgrammingError:(mysql.connector.errors.Programming错误)1064(42000):您的SQL语法有错误;请查看与MySQL服务器版本对应的手册,了解在“%(param_1)s=coupleproposition”附近使用的正确语法。
volunteerID
'在第3行[SQL:'选择coupupproposal.id作为coupuproposal_id,coupuproposal。
participantID
作为
coupleproposal_participantID
,情侣提议。
志愿者ID
作为
coupleproposal_volunteerID
\nFROM coupleproposition\n其中%(param_1)s=coupleroposition。
参与者ID
OR%(param_1)s=耦合方案。
志愿者ID
'][参数:{'param_1':1}]
