javascript - 为什么 sequelize.sync() 不同步表，除非我将模态导入文件？

Question

我正在将 postgres 与 sequelize 一起使用。我正在尝试在数据库中创建一个 Products 表。在主脚本文件 (app.js) 上，我调用了 sequelize.sync() 以将模态与数据库同步。但是，无论我尝试了多少次，该表都没有在数据库中制作。执行的唯一查询是这个；

Executing (default): SELECT 1+1 AS result

但是，当我将模态导入 app.js 文件时，同步发生得很好。我真的对这种行为感到困惑。
这些是我的文件；
./utils/database.js

const { Sequelize } = require("sequelize");

module.exports = new Sequelize("mydatabase", "myname", "mypassword", {
  host: "localhost",
  dialect: "postgres",
  operatorsAliases: false,

  pool: {
    max: 5,
    min: 0,
    acquire: 30000,
    idle: 10000,
  },
});

./modals/product.js

const { Sequelize, DataTypes } = require("sequelize");

const sequelize = require("../utils/database.js");

const Product = sequelize.define("Product", {
  id: {
    type: DataTypes.UUID,
    defaultValue: Sequelize.UUIDV4,
    allowNull: false,
    primaryKey: true,
  },
  title: {
    type: DataTypes.STRING,
  },
  price: {
    type: DataTypes.DOUBLE,
    allowNull: false,
  },
  imageUrl: {
    type: DataTypes.STRING,
  },
  description: {
    type: DataTypes.STRING,
  },
});

// export the Modal
module.exports = Product;

./app.js

const sequelize = require("./utils/database.js");

sequelize.sync()
  .then(() => {

    // listen
    app.listen(3000, () => {
      console.log("Server running...");
    });

    
  })
  .catch((error) => {
    console.log(error);
  });

上面的代码同步失败。但是如果我将模态导入到这个文件中，它就可以正常工作。

const sequelize = require("./utils/database.js");

// importing Product modal
const Product = require("./models/product.js");

    
    sequelize.sync()
      .then(() => {
    
        // listen
        app.listen(3000, () => {
          console.log("Server running...");
        });
    
        
      })
      .catch((error) => {
        console.log(error);
      });

如果要使用 sync() 函数，是否总是需要将所有模态导入 app.js 文件？

Answer 1

稍微改变你的文件结构，尝试如下
./utils/database.js

const { Sequelize } = require("sequelize");

const sequelize = new Sequelize("mydatabase", "myname", "mypassword", {
  host: "localhost",
  dialect: "postgres",
  operatorsAliases: false,

  pool: {
    max: 5,
    min: 0,
    acquire: 30000,
    idle: 10000,
  },
});

const db = {};

db.Sequelize = Sequelize;
db.sequelize = sequelize;

module.exports = db;

./modals/product.js

const { DataTypes } = require("sequelize");

const db = require("../utils/database.js");

const Product = db.sequelize.define("Product", {
  id: {
    type: DataTypes.UUID,
    defaultValue: db.Sequelize.UUIDV4,
    allowNull: false,
    primaryKey: true,
  },
  title: {
    type: DataTypes.STRING,
  },
  price: {
    type: DataTypes.DOUBLE,
    allowNull: false,
  },
  imageUrl: {
    type: DataTypes.STRING,
  },
  description: {
    type: DataTypes.STRING,
  },
});

// export the Modal
module.exports = Product;