javascript - 如何在 JavaScript 中通过 MySQL 建立多对多关系？

Question

我有 2 个模型，他们给出了 n:m 关系:老师、类(class)现在我想做一个查询来显示学生当前负责的类(class)(不是表中的所有类(class))。

这是我的类(class)模型:

module.exports = (sequelize, DataTypes) => {
var Model = sequelize.define('Class', {
    name          : DataTypes.STRING,
    category      : {type: DataTypes.STRING, unique: true},
    day           : DataTypes.ENUM('Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday'),
    hour          : DataTypes.STRING,
});

Model.associate = function(models){
    this.Students = this.belongsToMany(models.Student, {through: 'StudentClass'});
};
Model.associate = function(models){
    this.Staffs = this.belongsToMany(models.Staff, {through: 'ClassTeacher'});
};

Model.prototype.toWeb = function (pw) {
    let json = this.toJSON();
    return json;
};

return Model;

教师模型:

module.exports = (sequelize, DataTypes) => {
var Model = sequelize.define('Staff', {
    first     : DataTypes.STRING,
    last      : DataTypes.STRING,
    email     : {type: DataTypes.STRING, allowNull: true, unique: true, validate: { isEmail: {msg: "Email invalid."} }},
    phone     : {type: DataTypes.STRING, allowNull: true, unique: true, validate: { len: {args: [7, 20], msg: "Phone number invalid, too short."}, isNumeric: { msg: "not a valid phone number."} }},
    password  : DataTypes.STRING,
    role      : DataTypes.ENUM('Head', 'Teacher'),
});

Model.associate = function(models){
    this.Students = this.belongsToMany(models.Student, {through: 'TeacherStudent'});
};
Model.associate = function(models){
    this.Classes = this.belongsToMany(models.Class, {through: 'TeacherClass'});
};

我发现并尝试的是:

  Class.findAll({
    attributes: ['id', 'name'],
    include: [{
        model:Staff,
        attributes: ['first', 'last'],
        through: {
            attributes: ['StaffId', 'ClassId'],
            // where:{ClassId:1}
        }
      }]
}).then(classes => {
   res.send(classes);
});

但它向我显示了所有类(class)。

预先感谢您的帮助。

Answer 1

How to implement many to many association in sequelize
我认为您还没有关联两个表之间的关系，请查看上面提到的链接，它可能会帮助您理解我要解释的内容。