在Flask REST API代码中生成SQLite数据库

Question

我是REST API的新手，并开始使用Flask、SQLAlchemy&棉花糖。这是我的app.py文件：

from flask import Flask, request, jsonify
from flask_sqlalchemy import SQLAlchemy
from flask_marshmallow import Marshmallow
import os
# Initialize App
app = Flask(__name__)
basedir = os.path.abspath(os.path.dirname(__file__))
# Database Setup
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + os.path.join(basedir, 'db.sqlite')
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
# Init db
db = SQLAlchemy(app)
# Init marshmallow
ma = Marshmallow(app)

# Product Class/Model
class Product(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(100), unique=True)
description = db.Column(db.String(200))
price = db.Column(db.Float)
qty = db.Column(db.Integer)
def __init__(self, name, description, price, qty):
self.name = name
self.description = description
self.price = price
self.qty = qty

# Product Schema
class ProductSchema(ma.Schema):
class Meta:
fields = ('id', 'name', 'description', 'price', 'qty')

# Init Schema
product_schema = ProductSchema()
products_schema = ProductSchema(many=True)

# Create Product
@app.route('/product', methods=['POST'])
def add_product():
name = request.json['name']
description = request.json['description']
price = request.json['price']
qty = request.json['qty']
new_product = Product(name, description, price, qty)
db.session.add(new_product)
db.session.commit()
return product_schema.jsonify(new_product)

# Get All Products
@app.route('/receive', methods=['GET'])
def get_products():
all_products = Product.query.all()
result = products_schema.dump(all_products)
return jsonify(result)

# Run the Server
if __name__ == '__main__':
app.run(debug=True)

为了生成SQLite数据库，我必须打开python交互式shell，然后在那里我必须这样做：

from app import db
db.create_all()

但我必须从app.py本身生成数据库，所以我在app.py中插入了相同的命令，但它给了我错误：

OperationalError: (sqlite3.OperationalError) no such table: product

如何从app.py生成数据库？

Answer 1

您将db.create_all((放在哪里？错误可能只是放置的结果。当我将您的代码复制并粘贴到PyCharm(运行Python 3.7(中时，当我放置时，它会创建DB fine

db.create_all() 

之前

# Run the Server
if __name__ == '__main__':
app.run(debug=True)

如果在实例化db对象之前尝试运行db.create_all((，它将抛出一个错误，因为db还不存在。

您不应该使用"；从应用程序导入数据库"；这完全是因为db对象是在顶部声明的。