javascript - SequelizeEagerLoadingError，无法使用包含获取数据

Question

我使用 Sequelize.js 向数据库发出请求。我有两个表之间的多对多关系，我做了第三个连接表。这是我的三张 table 。 polit_in_article 是连接表。

政治家.js:

module.exports = (sequelize, DataTypes) => {
    const Politician = sequelize.define('politician', {
        ...
    });

    Politician.associate = (models) => {
        Politician.hasMany(models.Polit_in_article, {
            foreignKey: 'politicianId',
            as: 'polit_in_articles',
        });
    };

    return Politician;
};

文章.js:

module.exports = (sequelize, DataTypes) => {
    const Article = sequelize.define('article', {
        ...
    });

    Article.associate = (models) => {
        Article.hasMany(models.Politician, {
            foreignKey: 'articleId',
            as: 'polit_in_articles'
        });
    };
    return Article;
};

polit_in_article.js:

module.exports = (sequelize, DataTypes) => {
    const Polit_in_article = sequelize.define('polit_in_article', {
        times_mentioned: DataTypes.INTEGER,
    });
    Polit_in_article.associate = (models) => {
        Polit_in_article.belongsTo(models.Article, {
            // foreignKey: 'articleId',
            as: 'articles',
        });
        Polit_in_article.belongsTo(models.Politician, {
            // foreignKey: 'politicianId',
            as: 'politicians',
        });
    };

    return Polit_in_article;
};

这是我的 Controller (不确定这是否是正确的调用方式):

const Sequelize = require('sequelize');

const Article = require('../models').Article;
const Politician = require('../models').Politician;
const Polit_in_article = require('../models').Polit_in_article;

const Op = Sequelize.Op;

module.exports = {
    getAllArticlesOfPolitician(req) {
        return Article
            .findAll({
                include: [{
                    model: Polit_in_article,
                    include: [{
                        model: Politician,
                        where: {
                            lastname: req.query.politicianLastName,
                        }
                    }],
                }],
            }).then(response => response)
            // .catch(err => err);
    }
};

有了这个，我得到了一个错误 SequelizeEagerLoadingError: polit_in_article is not associated to article 。我可能错过了一些东西，但我真的不知道该怎么做。我试图使文章表具有关联 as: 'polit_in_articles' ，这一直有效，直到我需要将政治家表也包含在查询中。

Answer 1

您需要在关联中使用 through 关键字。 Articles 将有 politicians through Polit_in_article 模型，但是由于您只是在其上使用主键，因此您可以对其进行推断并省略 polit_in_article.js 并仅使用字符串来命名表。

Politician.associate = (models) => {
  Politician.hasMany(models.Article, {
    foreignKey: 'politicianId',
    through: 'polit_in_article',
    as: 'articles',
  });
};

Article.associate = (models) => {
  Article.hasMany(models.Politician, {
    foreignKey: 'articleId',
    through: 'polit_in_article',
    as: 'politicians',
  });
};

现在您可以通过指定 as 和 through 来查询连接表。

getAllArticlesOfPolitician(req) {
  return Article.findAll({
    include: [{
      model: Politician,
      as: 'politicians',
      through: 'polit_in_article',
      where: {
        lastname: req.query.politicianLastName,
      },
    }],
  })
  .then(response => response)
  .catch(err => err);
}