python - 没有名为 'backend' 的模块

Question

我正在尝试将我的代码分离到文件中。当我尝试从另一个文件导入任何变量时，出现以下错误:

File ".\app.py", line 2, in <module>
    from backend.Measure import Measure,MeasurementSchema,measure_schema,measures_schema
ModuleNotFoundError: No module named 'backend'

我有 3 个文件:

• app.py

  from flask import Flask, Request, jsonify
  from backend.Measure import Measure,MeasurementSchema,measure_schema,measures_schema
  from flask_sqlalchemy import SQLAlchemy
  
  app = Flask(__name__)
  
  db = SQLAlchemy(app)
  
  
  @app.route('/api/measures')
  def getAllMeasurements():
      results = Measure.query.all()
      return measures_schema.jsonify(results)
  

• Measure.py

  from flask_marshmallow import Marshmallow
  from backend.app import app
  from backend.app import db
  
  ma = Marshmallow(app)
  
  class Measure(db.Model):
      __tablename__ = 'measurements'
      id = db.Column(db.Integer, primary_key=True)
      timestamp = db.Column(db.DateTime, auto_now_add=True)
      temperature = db.Column(db.Float)
  
      def __init__(self, timestamp, temperature):
          self.timestamp = timestamp
          self.temperature = temperature
  
  class MeasurementSchema(ma.Schema):
      class Meta:
          fields = ('id', 'timestamp', 'temperature')
  
  measure_schema = MeasurementSchema()
  measures_schema = MeasurementSchema(many=True)
  

• db.py

  from sqlalchemy import create_engine
  
  server = 'localhost'
  database = 'TESTDB'
  driver = 'SQL Server Native Client 11.0'
  connection_string = f'mssql+pyodbc://@{server}/{database}?trusted_connection=yes&driver={driver}'
  
  app.config['SQLALCHEMY_DATABASE_URI'] = connection_string
  app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
  
  engine = create_engine(connection_string)
  connection = engine.connect()
  

所有文件都在 backend 文件夹中，如下图所示

我错过了什么？

Answer 1

如果你想从同一个文件夹导入文件，你应该这样做。

在 Measure.py 中

from .app import app
from .app import db

在 app.py 中

from .Measure import Measure,MeasurementSchema,measure_schema,measures_schema