Question

如何通过sequelize（nodejs）正确使用嵌套包含查询

我带有sequelize的嵌套包含查询给了我这个错误

"category is associated to course using an alias. You've included an alias (Category), but it does not match the alias defined in your association."

我想要的是从用户列表中获取的所有课程，然后从中获取所有课程，然后从中获取所有类别的列表

我不知道我做错了什么，我只需要它可以工作，对Node.js还是很新

这是代码

export default {
  Query: {
    users: combineResolvers(isAdmin, async (parent, args, { models }) => {
      return await models.User.findAll();
    }),
  },  
  User: { 
    messages: async (user, args, { models }) => {
      return await models.Message.findAll({
        where: { userId: user.id }, 
      });
    },     
    tcourses: async (user, args, { models }) => {
      return await models.TCourses.findAll({
        where: { UserId: user.id },
        include: [{model: models.Course, as: 'Course', include: [{model: models.Category, as: 'Category'}]}]
      })
    }
  },
}

这是我的课程模型代码

const tcourses = (sequelize, DataTypes) => {
    const TCourses = sequelize.define('tcourses', {
        id: {
            type: DataTypes.INTEGER,
            autoIncrement: true,
            unique: true,
            primaryKey: true,
            field: 'id'
        },
    }, {
        timestamps: false
    });

    TCourses.associate = models => {
        TCourses.belongsTo(models.Course,{ as: 'Course', required: false})
        TCourses.belongsTo(models.User,{ as: 'User'})
    };
    return TCourses;
};
export default tcourses;

这是我的课程模型代码

const course = (sequelize, DataTypes) => {
    const Course = sequelize.define('course', {
        Title: {
            type: DataTypes.STRING,
            validate: {
                notEmpty: {
                    args: true,
                    msg: 'Enter Course Title'
                }
            }, 
        },
    }, {
        timestamps: false
    })
    Course.associate = models => {
        Course.belongsTo(models.Category, { as: 'Cat'})
        Course.hasMany(models.Requirements,{onDelete: 'CASCADE', foreignKey: 'CourseId'})
        Course.belongsTo(models.User, { as: 'Owners'})
        Course.hasMany(models.Audience,{onDelete: 'CASCADE', foreignKey: 'CourseId'})
        Course.hasMany(models.TCourses,{onDelete: 'CASCADE', foreignKey: 'CourseId'})
    };
    return Course
  }; 
  export default course

这是我的类别模型代码

const category = (sequelize, DataTypes) => {
    const Category = sequelize.define('category', {
            catName: {
                type: DataTypes.STRING,
                validate: {
                    notEmpty: {
                        args: true,
                        msg: 'Enter Category name'
                    }
                },
            },
    }, {
            timestamps: false
    });

    Category.associate = models => {
        Category.hasMany(models.Course,{onDelete: 'CASCADE',  foreignKey: 'CatId'})
        Category.hasMany(models.TCategory,{onDelete: 'CASCADE', foreignKey: 'CategoryId'})
    };
    return Category;
};

  export default category;

请问如何使它工作

Answer 1

您必须在include语句和定义关联时为模型提供相同的别名。

错误也指定了相同的内容

"category is associated to course using an alias. You've included an alias (Category), but it does not match the alias defined in your association."

查询数据库时，您已将类别表的别名指定为类别

models.TCourses.findAll({
    where: { UserId: user.id },
    include: [{model: models.Course, as: 'Course', include: [{model: models.Category, as: 'Category'}]}]
  })

在“课程”模型中，您已将关联定义为 Cat

Course.belongsTo(models.Category, { as: 'Cat'})

现在您必须使其相同，即在两个地方都使用 Cat 或 Catgory 。

如何在节点（mysql）中正确使用带有sequelize的嵌套包含查询

1 个答案: