没有名为“backend”的模块

Question

嗨，我想把我的代码分成文件。什么时候我试图从另一个文件导入任何变量，但出现以下错误：

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

我有3个文件：

• 应用程序副本

  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)
  

• 测量.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)
  

• 数据库

      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()
  

所有文件都在后端文件夹中，如下图所示1

我错过了什么？在

Answer 1

如果要从同一个文件夹导入文件，应该这样做。在

在测量.py在

from .app import app
from .app import db

在应用程序副本在

^{pr2}$