使用 .ejs 模板显示数据时，使用 Sequelize 的 hasOne 关联不起作用

Question

我使用 ORM Sequelize 定义了 Customer 表和 Address 表之间的一对一关系

Customer.js源码如下：

// One to One Relationship

// Customer.js
// Include Sequelize module. 
const Sequelize = require('sequelize');
const Datatypes = require('Sequelize');
const path = require("path");


// Import sequelize object, 
// Database connection pool managed by Sequelize. 
// Import db_sequelize
const db_sequelize = require(path.join(__dirname,'..','config','db_sequelize.js'));


const Customer = db_sequelize.define('Customer', { 

    customer_id:{ 

        // Sequelize module has INTEGER Data_Type. 
        type:Datatypes.INTEGER, 

        // To increment user_id automatically. 
        autoIncrement:true, 

        // user_id can not be null. 
        allowNull:false, 

        // For uniquely identify user. 
        primaryKey:true
    }, 

    first_name: { type: Datatypes.STRING, allowNull:true }, 

    last_name: { type: Datatypes.STRING, allowNull:true }, 

    email: { type: Datatypes.STRING, allowNull:true},

    address_id: { type: Datatypes.INTEGER, allowNull:true},


    // dates => current time 
    myDate: { type: Datatypes.DATE, 
        defaultValue: Sequelize.NOW }, 

    // Timestamps 
    createdAt: Datatypes.DATE, 
    updatedAt: Datatypes.DATE, 
}); 

// Exporting Customer, using this constant 
// we can perform CRUD operations on 
// 'Customer' table. 
console.log(Date() + " " + "Model Customer has been defined");
module.exports = Customer;

Address.js源码如下：

// Address.js
// Include Sequelize module. 
const Sequelize = require('sequelize');
const Datatypes = require('sequelize');
const path = require("path");


// Import sequelize object, 
// Database connection pool managed by Sequelize. 
// Import db_sequelize
const db_sequelize = require(path.join(__dirname,'..','config','db_sequelize.js'));


const Address = db_sequelize.define('Address', { 

    address_id:{ 

        // Sequelize module has INTEGER Data_Type. 
        type:Datatypes.INTEGER, 

        // To increment user_id automatically. 
        autoIncrement:true, 

        // user_id can not be null. 
        allowNull:false, 

        // For uniquely identify user. 
        primaryKey:true
    }, 

    address: { type: Datatypes.STRING, allowNull:true }, 

    postal_code: { type: Datatypes.STRING, allowNull:true }, 

    district: { type: Datatypes.STRING, allowNull:true},

    // dates => current time 
    myDate: { type: Datatypes.DATE, 
            defaultValue: Datatypes.NOW }, 

    // Timestamps 
    createdAt: Datatypes.DATE, 
    updatedAt: Datatypes.DATE, 
});

const Customer = require(path.join(__dirname,'..','models', 'Customer.js'));


// 1:1 Relation between Customer and Address
// Each Customer has only One Address

Customer.hasOne(Address, {
    foreignKey: {
        name: 'address_id'
    }
});
Address.belongsTo(Customer, {
    foreignKey: 'address_id'
});

// Exporting Address, using this constant 
// we can perform CRUD operations on 
// 'Address' table. 
console.log(Date() + " " + "Model Address has been defined");
module.exports = Address;

显示与客户关联的地址值时，无需使用 .ejs 模板即可正确显示地址

// TEST ONE TO ONE RELATIONSHIP
// Get Customer address for customer_id equal 1
let  get_address_customer_id = async function(){
  try {
      let customer = await Customer.findByPk(1);
      // find by primary key
      let customerAddress = await customer.getAddress();
      //Address belongs to Customer
      //then customer.getAddress();
      //get the address
      //for customer_id equal 1
      console.log("NUI del Customer    : ", customer.customer_id);
      console.log("Customer Name : ", customer.first_name + " " + customer.last_name);
      console.log("Customer Address  : ", customerAddress.address);      
  } catch (error) { console.error("Error log", error);}
}

get_address_customer_id();

NUI 客户：1

客户姓名：名字 1 姓氏 1

客户地址：地址1

但是，使用 .ejs 模板时，客户和地址之间的一对一关系不起作用。在一对一关系测试中，我使用 let customerAddress = wait customer.getAddress();但是，我不在 .ejs 模板中使用它，我认为这就是区别。但是，假设如果 1 对 1 关系有效，您应该获得链接到客户的地址

// list_customers.js

// Set router
const express = require("express");
const router = express.Router();
const path = require("path");

router.get("/", async (req, res) => {    
    
    //Get the model for Customer
    const Customer = require(path.join(__dirname,'..', 'models', 'Customer.js'));

    // Find all Customers
    const customers = await Customer.findAll();

    res.render("view_listar_customers.ejs", { model: customers });


});

module.exports = router;

显示Customer和Address关系数据的.ejs模板代码如下：

    <tbody>
      <% for (const customer of model) { %>
        <tr>
          <td><%= customer.customer_id %></td>
          <td><%= customer.first_name %>, <%= customer.last_name %></td>
          <td><%= customer.address %></td>
          <td class="d-print-none">
            <a class="btn btn-sm btn-warning" href="/edit_customer/<%= customer.customer_id %>">Edit</a>
            <a class="btn btn-sm btn-danger" href="/delete_customer/<%= customer.customer_id %>">Delete</a>
          </td>
        </tr>
      <% } %>
    </tbody>

解决问题的指南将不胜感激。谢谢你。

Answer 1

我找到了使用 Sequelize 的原始查询来显示数据的替代方法。我附上了源代码部分，以防对于想要使用 ORM Sequelize 的一对一关系显示所有记录的查询结果并将结果显示在 .ejs 模板中的人有用。

router.get("/", async (req, res) => {    
    
    //Get the model for Customer and Address
    const Customer = require(path.join(__dirname,'..', 'models', 'Customer.js'));
    const Address = require(path.join(__dirname,'..', 'models', 'Address.js'));


    const db_sequelize = require(path.join(__dirname, '..','config', 'db_sequelize.js'));

    // Inner Join
    const [customers, metadata] = await db_sequelize.query(
    "SELECT C.first_name, C.last_name, A.address FROM Customer C INNER JOIN Address A ON C.AddressId=A.id");
                                                          
    // Display Clients with their addresses
    res.render("view_listar_customers.ejs", { model: customers });


});