Yeah it took me about 3 hours to realize that in my actual code, I made a typo in the __init__ so that I was assigning the uuid to the wrong attribute/column. So embarassing :(
On Monday, March 19, 2018 at 11:04:04 PM UTC-4, Peter Lai wrote: > > As seen at: > https://stackoverflow.com/questions/49374458/how-to-propagate-subclass-primary-key-to-base-class-primary-key-when-creating-ne > > I'm running into a problem where I am using joined table inheritance where > the base class carries "upstream" relationships: > > class EmployeeType(Base): > __tablename__ = 'employee_types' > > emp_type = Column(String(50), primary_key=True) > emp_type_description = Column(Text) > # we want to constrain the EmployeeTypes > > # UUID is a custom TypeDecorator that generates a UUID correctly for all > backends > > class Employee(Base): > > __tablename__ = 'employees' > > emp_id = Column(UUID, primary_key=True) > emp_type = Column(String(50), ForeignKey(EmployeeType.emp_type)) > > emp_groups = relationship(EmployeeMembership, backref='employee') > > __mapper_args__ = { > 'polymorphic_on': emp_type > } > > # this is a one-to-many association membership-type of objectclass > EmployeeMembership(Base): > __tablename__ = 'employee_membership' > > emp_id = Column(UUID, ForeignKey(Employee.emp_id), primary_key=True) > group = Column(String(25), primary_key=True) > > > class Engineer(Employee): __tablename__ = 'engineers' emp_id = Column(UUID > , ForeignKey(Employee.emp_id), primary_key=True) # emp_name belongs to > subclass because within the subclass it needs to be unique, but not unique > across subclasses # There can be 2 different employees (emp_id are > different) named 'Leeroy Jenkins' one is a manager and one is an engineer. > > > emp_name = Column(String(50), unique=True, nullable=False) > > engineer_attr = Column(Text) > > __mapper_args__ = { > 'polymorphic_identity': 'engineer' > } > > # create a new UUID if I don't give one (new Engineer/Employee) > def __init__(self, *args, **kwargs): > if 'emp_id' not in kwargs: > self.emp_id = function_to_generate_uuid() > > super(Engineer,self).__init__(*args, **kwargs)) > class Manager(Employee): > __tablename__ = 'manager' > > emp_id = Column(UUID, ForeignKey(Employee.emp_id), primary_key=True) > > # emp_name belongs to subclass because within the subclass it needs to be > unique, but not unique across subclasses > # There can be 2 different employees (emp_id are different) named 'Leeroy > Jenkins' one is a manager and one is an engineer. > emp_name = Column(String(50), unique=True, nullable=False) > > manager_blah = Column(Text) > > __mapper_args__ = { > 'polymorphic_identity': 'manager' > } > > # create a new UUID if I don't give one (new Manager/Employee) > def __init__(self, *args, **kwargs): > if 'emp_id' not in kwargs: > self.emp_id = function_to_generate_uuid() > > super(Manager, self).__init__(*args, **kwargs)) > > > The problem is when I go to create either an Engineer or Manager: > > new_emp = Engineer(emp_name='Leeroy Jenkins') > session = Session() > session.add(new_emp) > session.commit() > > > I get: > > python27\lib\site-packages\sqlalchemy\sql\crud.py:692: SAWarning: Column > 'employees.emp_id'is marked as a member of the primary key for table > 'employees', but has no Python-sideor server-side default generator > indicated, nor does it indicate 'autoincrement=True'or 'nullable=True', and > no explicit value is passed. Primary key columns typically may not > store NULL. > util.warn(msg)(psycopg2.IntegrityError) null value in column "emp_id" > violates not-null constraint > DETAIL: Failing row contains (null, engineer).[SQL: 'INSERT INTO employees > (emp_type) VALUES (%(emp_type)s)'] [parameters: {'emp_type': u'engineer'}] > > > What do I need to do to get my instance of base class created properly > when I create my subclass? I'm still on SQLAlchemy 1.1.13 and py27 > > Thanks > -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
