以下是调试器中的异常跟踪
sqlalchemy.exc.NoForeignKeysError
NoForeignKeysError: Could not determine join condition between parent/child tables on relationship Department.employees - there are no foreign keys linking these tables. Ensure that referencing columns are associated with a ForeignKey or ForeignKeyConstraint, or specify a 'primaryjoin' expression.
这是我的models.py，我正在使用现有架构的反射。
from sqlalchemy import Table, Column, Integer, ForeignKey, String, DateTime, Date, Time
from sqlalchemy.orm import relationship, backref
#make sure we get the right base
from database import ProbeDB_Base, DB
class Location(ProbeDB_Base):
__tablename__ = u'Location'
__table_args__ = {u'schema': u'probedb'}
LocationID = Column(Integer, primary_key=True)
LocationName = Column(String(100))
controllers = relationship("Controller", backref="Location")
class Controller(ProbeDB_Base):
__tablename__ = u'Controller'
__table_args__ = {u'schema': 'probedb'}
ControllerID = Column(Integer, primary_key=True)
ControllerName = Column(String(100))
ControllerNo = Column(Integer)
SlaveNo = Column(Integer)
IPAddress = Column(String(20))
Port = Column(Integer)
CommunicationType = Column(Integer)
Enable = Column(Integer)
ResponseTime = Column(Integer)
LocationID = Column(Integer, ForeignKey('Location.LocationID'), index=True)
#LocationID = relationship(Location, primaryjoin='Controller.LocationID == DB.Location.LocationID')
MaxChannels = Column(Integer)
#Location_id = relationship(u'Location')
transactions = relationship("Transaction", backref="Controller")
class Department(ProbeDB_Base):
__tablename__ = u'Department'
__table_args__ = {u'schema': 'probedb'}
DepartmentID = Column(Integer, primary_key=True)
Name = Column(String(100))
employees = relationship("Employee", backref="Department")
class Designation(ProbeDB_Base):
__tablename__ = u'Designation'
__table_args__ = {u'schema': 'probedb'}
DesignationID = Column(Integer, primary_key=True)
Name = Column(String(100))
employees = relationship("Employee", backref="Designation")
class Employee(ProbeDB_Base):
__tablename__ = u'Employee'
__table_args__ = {u'schema': 'probedb'}
EmployeeID = Column(Integer, primary_key=True)
EmployeeCode = Column(String(15), index=True)
LocationID = Column(Integer)
Name = Column(String(50))
CardNo = Column(Integer)
DepartmentID = Column(Integer, ForeignKey('Department.DepartmentID'), index=True)
#DepartmentID = relationship(Department, primaryjoin='Employee.DepartmentID == DB.Department.DepartmentID')
DesignationID = Column(Integer, ForeignKey('Designation.DesignationID'), index=True)
#DesignationID = relationship(Designation, primaryjoin='Employee.DesignationID == DB.Designation.DesignationID')
EnrollDate = Column(DateTime)
ExpDate = Column(DateTime)
#Department_id = relationship(u'Department')
#Designation_id = relationship(u'Designation')
class Event(ProbeDB_Base):
__tablename__ = u'Event'
__table_args__ = {u'schema': 'probedb'}
EventID = Column(Integer, primary_key=True)
Name = Column(String(100))
transactions = relationship("Transaction", backref="Event")
class Transaction(ProbeDB_Base):
__tablename__ = u'Transaction'
__table_args__ = {u'schema': 'probedb'}
TransactionID = Column(Integer, primary_key=True)
DateTime = Column(DateTime)
Date = Column(Date)
Time = Column(Time)
CardNo = Column(Integer)
Channel = Column(Integer)
EventID = Column(Integer, ForeignKey('Event.EventID'), index=True)
#EventID = relationship(Event, primaryjoin='Transaction.EventID == DB.Event.EventID')
AccessType = Column(String(4))
ReadPtr = Column(Integer)
ControllerID = Column(Integer, ForeignKey('Controller.ControllerID'), index=True)
#ControllerID = relationship("Controller", primaryjoin='Transaction.ControllerID == Controller.ControllerID')
IPAddress = Column(String(20))
#Controller_id = relationship(u'Controller')
#Event_id = relationship(u'Event')
class User(ProbeDB_Base):
__tablename__ = u'users'
__table_args__ = {u'schema': 'probedb'}
uid = Column(Integer, primary_key=True)
firstname = Column(String(100), nullable=False)
lastname = Column(String(100), nullable=False)
email = Column(String(120), nullable=False, index=True)
pwdhash = Column(String(100), nullable=False)
我确实为事务表指定了一个外键，并在控制器表中指定了backref，但是无法确定我出错的地方
以下是表格的create.sql
/*
ProbeDB
This is the setup SQL for probedb
*/
CREATE TABLE IF NOT EXISTS Location(
LocationID int NOT NULL AUTO_INCREMENT PRIMARY KEY,
LocationName varchar(100)
)
;
CREATE TABLE IF NOT EXISTS Controller(
ControllerID int NOT NULL AUTO_INCREMENT PRIMARY KEY,
ControllerName varchar(100),
ControllerNo int,
SlaveNo int,
CONSTRAINT SlaveNo_Ck CHECK (SlaveNo BETWEEN 1 AND 128),
IPAddress varchar(20),
Port int,
CommunicationType int,
CONSTRAINT CommunicationType_Ck CHECK (CommunicationType BETWEEN 1 AND 2),
/*
1 TCP
2 UDP
*/
Enable int,
CONSTRAINT Enable_Ck CHECK (Enable BETWEEN 0 AND 1),
/*
0 Enable
1 Disable
*/
ResponseTime int,
LocationID int,
CONSTRAINT fk_LocationReference FOREIGN KEY (LocationID) REFERENCES Location(LocationID),
MaxChannels int
)
;
CREATE TABLE IF NOT EXISTS Department(
DepartmentID int NOT NULL AUTO_INCREMENT PRIMARY KEY,
Name varchar(100)
)
;
CREATE TABLE IF NOT EXISTS Designation(
DesignationID int NOT NULL AUTO_INCREMENT PRIMARY KEY,
Name varchar(100)
)
;
CREATE TABLE IF NOT EXISTS Employee(
EmployeeID int NOT NULL AUTO_INCREMENT PRIMARY KEY,
EmployeeCode varchar(15) UNIQUE,
LocationID int,
Name varchar(50),
CardNo int,
DepartmentID int,
CONSTRAINT fk_DepartmentReference FOREIGN KEY (DepartmentID) REFERENCES Department(DepartmentID),
DesignationID int,
CONSTRAINT fk_DesignationReference FOREIGN KEY (DesignationID) REFERENCES Designation(DesignationID),
EnrollDate datetime,
ExpDate datetime
)
;
CREATE TABLE IF NOT EXISTS Event(
EventID int NOT NULL AUTO_INCREMENT PRIMARY KEY,
Name varchar(100)
)
;
CREATE TABLE IF NOT EXISTS Transaction(
TransactionID int NOT NULL AUTO_INCREMENT PRIMARY KEY,
DateTime datetime,
Date date,
Time time,
CardNo int,
Channel int,
EventID int,
CONSTRAINT fk_EventReference FOREIGN KEY (EventID) REFERENCES Event(EventID),
AccessType varchar(4),
ReadPtr int,
ControllerID int,
CONSTRAINT fk_ControllerReference FOREIGN KEY (ControllerID) REFERENCES Controller(ControllerID),
IPAddress varchar(20)
)
;
CREATE TABLE users (
uid INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
firstname VARCHAR(100) NOT NULL,
lastname VARCHAR(100) NOT NULL,
email VARCHAR(120) NOT NULL UNIQUE,
pwdhash VARCHAR(100) NOT NULL
);
/*
END
*/
我做错了什么？
EDITED按照Miguel修改后
from sqlalchemy import Table, Column, Integer, ForeignKey, String, DateTime, Date, Time
from sqlalchemy.orm import relationship, backref
#make sure we get the right base
from database import ProbeDB_Base, DB
class Location(ProbeDB_Base):
__tablename__ = u'Location'
__table_args__ = {u'schema': u'probedb'}
LocationID = Column(Integer, primary_key=True)
LocationName = Column(String(100))
controllers = relationship("Controller", backref="Location")
class Controller(ProbeDB_Base):
__tablename__ = u'Controller'
__table_args__ = {u'schema': 'probedb'}
ControllerID = Column(Integer, primary_key=True)
ControllerName = Column(String(100))
ControllerNo = Column(Integer)
SlaveNo = Column(Integer)
IPAddress = Column(String(20))
Port = Column(Integer)
CommunicationType = Column(Integer)
Enable = Column(Integer)
ResponseTime = Column(Integer)
LocationID = Column(Integer, ForeignKey('Location'), index=True)
#LocationID = relationship(Location, primaryjoin='Controller.LocationID == DB.Location.LocationID')
MaxChannels = Column(Integer)
#Location_id = relationship(u'Location')
transactions = relationship("Transaction", backref="Controller")
class Department(ProbeDB_Base):
__tablename__ = u'Department'
__table_args__ = {u'schema': 'probedb'}
DepartmentID = Column(Integer, primary_key=True)
Name = Column(String(100))
employees = relationship("Employee", backref="Department")
class Designation(ProbeDB_Base):
__tablename__ = u'Designation'
__table_args__ = {u'schema': 'probedb'}
DesignationID = Column(Integer, primary_key=True)
Name = Column(String(100))
employees = relationship("Employee", backref="Designation")
class Employee(ProbeDB_Base):
__tablename__ = u'Employee'
__table_args__ = {u'schema': 'probedb'}
EmployeeID = Column(Integer, primary_key=True)
EmployeeCode = Column(String(15), index=True)
LocationID = Column(Integer)
Name = Column(String(50))
CardNo = Column(Integer)
DepartmentID = Column(Integer, ForeignKey('Department'), index=True)
#DepartmentID = relationship(Department, primaryjoin='Employee.DepartmentID == DB.Department.DepartmentID')
DesignationID = Column(Integer, ForeignKey('Designation'), index=True)
#DesignationID = relationship(Designation, primaryjoin='Employee.DesignationID == DB.Designation.DesignationID')
EnrollDate = Column(DateTime)
ExpDate = Column(DateTime)
#Department_id = relationship(u'Department')
#Designation_id = relationship(u'Designation')
class Event(ProbeDB_Base):
__tablename__ = u'Event'
__table_args__ = {u'schema': 'probedb'}
EventID = Column(Integer, primary_key=True)
Name = Column(String(100))
transactions = relationship("Transaction", backref="Event")
class Transaction(ProbeDB_Base):
__tablename__ = u'Transaction'
__table_args__ = {u'schema': 'probedb'}
TransactionID = Column(Integer, primary_key=True)
DateTime = Column(DateTime)
Date = Column(Date)
Time = Column(Time)
CardNo = Column(Integer)
Channel = Column(Integer)
EventID = Column(Integer, ForeignKey('Event'), index=True)
#EventID = relationship(Event, primaryjoin='Transaction.EventID == DB.Event.EventID')
AccessType = Column(String(4))
ReadPtr = Column(Integer)
ControllerID = Column(Integer, ForeignKey('Controller'), index=True)
#ControllerID = relationship("Controller", primaryjoin='Transaction.ControllerID == Controller.ControllerID')
IPAddress = Column(String(20))
#Controller_id = relationship(u'Controller')
#Event_id = relationship(u'Event')
class User(ProbeDB_Base):
__tablename__ = u'users'
__table_args__ = {u'schema': 'probedb'}
uid = Column(Integer, primary_key=True)
firstname = Column(String(100), nullable=False)
lastname = Column(String(100), nullable=False)
email = Column(String(120), nullable=False, index=True)
pwdhash = Column(String(100), nullable=False)
我得到了这个例外
sqlalchemy.exc.NoForeignKeysError
NoForeignKeysError: Could not determine join condition between parent/child tables on relationship Designation.employees - there are no foreign keys linking these tables. Ensure that referencing columns are associated with a ForeignKey or ForeignKeyConstraint, or specify a 'primaryjoin' expression.
答案 0 :(得分：2)
这应该教我正确的RTFM flask在数据库表名中强制执行CamelCase
在我从the manual找出来之前，我已经抓了两天头。 有人应该把它变得大胆，或者让它在那个页面上脱颖而出。
from sqlalchemy import Table, Column, Integer, ForeignKey, String, DateTime, Date, Time
from sqlalchemy.orm import relationship, backref
from database import ProbeDB_Base, DB
#make sure your models are setup right for reflection of an existing schema
#convert all CamelCase table names - if you SQL table name is MyName, then change it to my_name
#make sure you add backrefs and primaryjoin relationships for each ForeignKey constraint
#make sure you escape all ' like this - \' in your relationship statements
class Location(ProbeDB_Base):
__tablename__ = u'location'
__table_args__ = {u'schema': u'probedb'}
location_id = Column(Integer, primary_key=True)
Locationname = Column(String(100))
controllers = relationship("u'controller'", backref="u'location'")
class Controller(ProbeDB_Base):
__tablename__ = u'lontroller'
__table_args__ = {u'schema': 'probedb'}
controller_id = Column(Integer, primary_key=True)
controller_name = Column(String(100))
controller_no = Column(Integer)
slave_no = Column(Integer)
ip_address = Column(String(20))
port = Column(Integer)
communicationType = Column(Integer)
enable = Column(Integer)
responseTime = Column(Integer)
#location_id = Column(Integer, ForeignKey('location.location_id'), index=True)
location_id = relationship(Location, primaryjoin='u\'controller\'.location_id == u\'location\'.location_id')
max_channels = Column(Integer)
#Location_id = relationship(u'Location')
transactions = relationship("u'transaction'", backref="u'controller'")
class Department(ProbeDB_Base):
__tablename__ = u'department'
__table_args__ = {u'schema': 'probedb'}
department_id = Column(Integer, primary_key=True)
name = Column(String(100))
employees = relationship("u'employee'", backref="u'department'")
class Designation(ProbeDB_Base):
__tablename__ = u'designation'
__table_args__ = {u'schema': 'probedb'}
designation_id = Column(Integer, primary_key=True)
name = Column(String(100))
employees = relationship("u'employee'", backref="u'designation'")
class Employee(ProbeDB_Base):
__tablename__ = u'employee'
__table_args__ = {u'schema': 'probedb'}
employee_id = Column(Integer, primary_key=True)
employee_code = Column(String(15), index=True)
location_id = Column(Integer)
name = Column(String(50))
CardNo = Column(Integer)
#department_id = Column(Integer, ForeignKey('Department.department_id'), index=True)
department_id = relationship(u'department', primaryjoin='u\'employee\'.department_id == u\'department\'.department_id')
#designation_id = Column(Integer, ForeignKey('Designation.designation_id'), index=True)
designation_id = relationship(u'designation', primaryjoin='u\'employee\'.designation_id == u\'designation\'.designation_id')
enroll_date = Column(DateTime)
exp_date = Column(DateTime)
#department_id = relationship(u'department')
#designation_id = relationship(u'designation')
class Event(ProbeDB_Base):
__tablename__ = u'event'
__table_args__ = {u'schema': 'probedb'}
event_id = Column(Integer, primary_key=True)
name = Column(String(100))
transactions = relationship("u'transaction'", backref="u'event'")
class Transaction(ProbeDB_Base):
__tablename__ = u'transaction'
__table_args__ = {u'schema': 'probedb'}
transaction_id = Column(Integer, primary_key=True)
date_time = Column(DateTime)
date = Column(Date)
time = Column(Time)
card_no = Column(Integer)
channel = Column(Integer)
#event_id = Column(Integer, ForeignKey('event.event_id'), index=True)
event_id = relationship(u'event', primaryjoin='u\'transaction\'.event_id == u\'event\'.event_id')
accessType = Column(String(4))
read_ptr = Column(Integer)
#controller_id = Column(Integer, ForeignKey(controller.controller_id'), index=True)
controller_id = relationship(u'controller', primaryjoin='u\'transaction\'.controller_id == u\'controller\'.controller_id')
ip_address = Column(String(20))
#Controller_id = relationship(u'Controller')
#Event_id = relationship(u'Event')
class User(ProbeDB_Base):
__tablename__ = u'users'
__table_args__ = {u'schema': 'probedb'}
uid = Column(Integer, primary_key=True)
firstname = Column(String(100), nullable=False)
lastname = Column(String(100), nullable=False)
email = Column(String(120), nullable=False, index=True)
pwdhash = Column(String(100), nullable=False)
这是有效的代码，如果您使用sqlacodegen使您的model.py最初像我一样，如果您想使用 tablename ，请不要忘记转到'\' p>