我开始使用 sqlalchemy。 我在处理和粘贴示例代码时遇到操作错误

Question

I am just trying to get started using sqlalchemy. For whatever reason I can't get anything to work.

I installed sqlalchemy the import alone works. I tried to start following the code on this site:

https://www.pythoncentral.io/introductory-tutorial-python-sqlalchemy/

The code is as follows:

import os
import sys
from sqlalchemy import Column, ForeignKey, Integer, String
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import relationship
from sqlalchemy import create_engine

Base = declarative_base()

class Person(Base):
    __tablename__ = 'person'
    # Here we define columns for the table person
    # Notice that each column is also a normal Python instance attribute.
    id = Column(Integer, primary_key=True)
    name = Column(String(250), nullable=False)

class Address(Base):
    __tablename__ = 'address'
    # Here we define columns for the table address.
    # Notice that each column is also a normal Python instance attribute.
    id = Column(Integer, primary_key=True)
    street_name = Column(String(250))
    street_number = Column(String(250))
    post_code = Column(String(250), nullable=False)
    person_id = Column(Integer, ForeignKey('person.id'))
    person = relationship(Person)

# Create an engine that stores data in the local directory's
# sqlalchemy_example.db file.
engine = create_engine('sqlite:///sqlalchemy_example.db')

# Create all tables in the engine. This is equivalent to "Create Table"
# statements in raw SQL.
Base.metadata.create_all(engine)

I copied and pasted the code to create a table and I'm getting the following error

sqlalchemy.exc.OperationalError: (sqlite3.OperationalError) unable to open database file (Background on this error at: http://sqlalche.me/e/e3q8 )

I went to http://sqlalche.me/e/e3q8 and it seems to believe that adding pool_pre_ping=True to the engine would help resolve issue. It mentions a connection issues, but don't really understand how that can be since it's just creating the sqlite database.

I would really appreciate any advice on how I can fix this issue.

Edit: I put the specific code into my question.

Also I tried performing the code in pythonanywhere and it works as expected. Any guidance on what could be wrong with my machine would be appreciated.

Answer 1

So for whatever reason I needed to designate the absolute path of where the database needed to be. I updated my engine to be:

sqlite:///C:\\user\\file_path\\test.db

this allowed it to create the database. However I'd really prefer it just create the database in the current directory. If someone knows what I need to do to get that to work that would be great.