How to get rid of sqlalchemy.exc.NoReferencedTableError?
Here's some code related to the problem:
import sqlalchemy as sa import sqlalchemy.orm as orm import sqlalchemy.ext.declarative as dec SqlAlchemyBase = dec.declarative_base() __Session = None def create_session(): global __Session global_init() return __Session() def global_init(): global __Session if __Session: return conn_str = f'sqlite:///sqlite.db' engine = sa.create_engine(conn_str, echo=True, future=True) __Session = orm.sessionmaker(bind=engine) SqlAlchemyBase.metadata.create_all(engine)
User.py (error comes from User.department_id column)
import sqlalchemy from db_session import SqlAlchemyBase class User(SqlAlchemyBase): __tablename__ = 'users' id = sqlalchemy.Column(sqlalchemy.Integer, primary_key=True, autoincrement=True) department_id = sqlalchemy.Column(sqlalchemy.Integer, sqlalchemy.ForeignKey('departments.id'), nullable=True)
import sqlalchemy from db_session import SqlAlchemyBase class Departments(SqlAlchemyBase): __tablename__ = 'departments' id = sqlalchemy.Column(sqlalchemy.Integer, primary_key=True, autoincrement=True) chief = sqlalchemy.Column(sqlalchemy.Integer, sqlalchemy.ForeignKey("users.id")) members = sqlalchemy.orm.relationship("User", foreign_keys="User.department_id")
The error occurs whenever I try to access the 'users' table. Here's the error text:
sqlalchemy.exc.NoReferencedTableError: Foreign key associated with column 'users.department_id' could not find table 'departments' with which to generate a foreign key to target column 'id'
I've checked the sqlite.db file with database management software and there definitely is 'departments' table. I've printed the output of
and the 'departments' table is there, too, and even has the right name. I've tried to add something to the 'departments' table, but that also didn't help. All tables' names are set explicitly with tablename property, so sqlalchemy's automatic table naming isn't the problem. How do I get rid of this error?
Thanks to @snakecharmerb for the solution!
Turns out, I had to import the Departments class everywhere I used the Users model for sqlalchemy to find all tables.