關系表上的NodeJSPostgreSQLExpressSequelizeEagerLoadingError

我遇到了無法從 NodeJS PostgreSQL 和 Express 訪問關系資料表的問題。

首先，這是我的簡單表格：

如您所見，我的“jenis”表與“kategori”表有關聯，一個jenis可以有多個kategori，一個kategori應該只包含一個jenis。

這是我對 Postgres Sequelize 的遷移：

jenis-migration.js

"use strict";
module.exports = {
  up: async (queryInterface, Sequelize) => {
    await queryInterface.createTable("Umkm_Jenis", {
      id: {
        allowNull: false,
        autoIncrement: true,
        primaryKey: true,
        type: Sequelize.INTEGER,
      },
      nama: {
        type: Sequelize.STRING,
      },
      createdAt: {
        allowNull: false,
        type: Sequelize.DATE,
      },
      updatedAt: {
        allowNull: false,
        type: Sequelize.DATE,
      },
    });
  },
  down: async (queryInterface, Sequelize) => {
    await queryInterface.dropTable("Umkm_Jenis");
  },
};

分類遷移.js

"use strict";
module.exports = {
  up: async (queryInterface, Sequelize) => {
    await queryInterface.createTable("Umkm_Kategori", {
      id: {
        allowNull: false,
        autoIncrement: true,
        primaryKey: true,
        type: Sequelize.INTEGER,
      },
      jenis_id: {
        type: Sequelize.INTEGER,
        allowNull: false,
      },
      nama: {
        type: Sequelize.STRING,
        allowNull: false,
      },
      createdAt: {
        allowNull: false,
        type: Sequelize.DATE,
      },
      updatedAt: {
        allowNull: false,
        type: Sequelize.DATE,
      },
    });
  },
  down: async (queryInterface, Sequelize) => {
    await queryInterface.dropTable("Umkm_Kategori");
  },
};

jenis.model.js

"use strict";
const { Model } = require("sequelize");
module.exports = (sequelize, DataTypes) => {
  class Umkm_Jenis extends Model {
    /**
     * Helper method for defining associations.
     * This method is not a part of Sequelize lifecycle.
     * The `models/index` file will call this method automatically.
     */
    static associate(models) {
      // define association here
      this.hasMany(models.Umkm_Kategori, {
        foreignKey: "jenis_id",
        as: "umkm_kategori",
      });
    }
  }
  Umkm_Jenis.init(
    {
      nama: DataTypes.STRING,
    },
    {
      sequelize,
      modelName: "Umkm_Jenis",
      freezeTableName: true,
    }
  );
  return Umkm_Jenis;
};

分類模型.js

"use strict";
const { Model } = require("sequelize");
module.exports = (sequelize, DataTypes) => {
  class Umkm_Kategori extends Model {
    /**
     * Helper method for defining associations.
     * This method is not a part of Sequelize lifecycle.
     * The `models/index` file will call this method automatically.
     */
    static associate(models) {
      // define association here
      this.belongsTo(models.Umkm_Jenis, {
        foreignKey: "jenis_id",
        as: "umkm_jenis",
      });
    }
  }
  Umkm_Kategori.init(
    {
      jenis_id: DataTypes.INTEGER,
      nama: DataTypes.STRING,
    },
    {
      sequelize,
      modelName: "Umkm_Kategori",
      freezeTableName: true,
    }
  );
  return Umkm_Kategori;
};

我在 postgres 上為 jenis 和 kategori 表創建了一些播種機資料。

現在我希望我的 getAllKategori API 使用我建立的關系實際包含“jenis”表中的值。下面是我的 apiController 用于 categori ：

exports.findAllKategori = async (req, res) => {
  //check if theres a filter applied
  const nama = req.query.nama;
  const condition = nama ? { nama: { [Op.iLike]: `%${nama}%` } } : null;

  try {
    const response = Kategori.findAll({
      where: condition,
      include: [{ model: db.jenis, as: "umkm_jenis", required: false }],
    });
    const data = await response;
    return res.status(200).send(data);
  } catch (error) {
    console.log(error);
    return res.status(500).send(error);
  }
};

但是當我嘗試從 POSTMAN 訪問 API 時，它顯示 SequelizeEagerLoadingError。

如果我在 kategoriController 上評論了這一行：

  include: [{ model: db.jenis, as: "umkm_jenis", required: false }],

然后再次嘗試點擊api，它成功顯示了我的所有資料。

我已經在這個論壇上閱讀了一些類似的問題，但似乎沒有一個有效。

感謝您抽出寶貴時間！

更新

下面是模型/index.js 檔案

"use strict";

const fs = require("fs");
const path = require("path");
const Sequelize = require("sequelize");
const basename = path.basename(__filename);
const env = process.env.NODE_ENV || "development";
const config = require(__dirname   "/../config/config.json")[env];
const db = {};

let sequelize;
if (config.use_env_variable) {
  sequelize = new Sequelize(process.env[config.use_env_variable], config);
} else {
  sequelize = new Sequelize(
    config.database,
    config.username,
    config.password,
    config
  );
}

fs.readdirSync(__dirname)
  .filter((file) => {
    return (
      file.indexOf(".") !== 0 && file !== basename && file.slice(-3) === ".js"
    );
  })
  .forEach((file) => {
    const model = require(path.join(__dirname, file))(
      sequelize,
      Sequelize.DataTypes
    );
    db[model.name] = model;
  });

Object.keys(db).forEach((modelName) => {
  if (db[modelName].associate) {
    db[modelName].associate(db);
  }
});

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

db.kategori = require("./umkm_kategori")(sequelize, Sequelize);
db.jenis = require("./umkm_jenis")(sequelize, Sequelize);
db.produk = require("./umkm_produk")(sequelize, Sequelize);
db.review = require("./umkm_review")(sequelize, Sequelize);

module.exports = db;

控制臺日志（錯誤）

uj5u.com熱心網友回復：

您已經使用以下代碼段注冊了所有模型和關聯：

const model = require(path.join(__dirname, file))(
      sequelize,
      Sequelize.DataTypes
    );
    db[model.name] = model;

和

Object.keys(db).forEach((modelName) => {
  if (db[modelName].associate) {
    db[modelName].associate(db);
  }
});

所以這段代碼再次注冊模型，只需洗掉它并使用上面定義的模型名稱。

db.kategori = require("./umkm_kategori")(sequelize, Sequelize);
db.jenis = require("./umkm_jenis")(sequelize, Sequelize);
db.produk = require("./umkm_produk")(sequelize, Sequelize);
db.review = require("./umkm_review")(sequelize, Sequelize);

標籤：节点.js 数据库 PostgreSQL的 表达 sequelize.js

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