续集查找属于多对关联 [英] Sequelize Find belongsToMany Association

问题描述

我在两个表之间有一个关联m:n，如下所示:

I have an association m:n between two tables with sequelize like this:

课程

module.exports = function(sequelize, DataTypes) {

  var Course = sequelize.define('Course', {
     .....
    },
    {
      associate: function(models){
        Course.hasMany(models.Schedule);
        Course.belongsTo(models.Period);
        Course.belongsTo(models.Room);
        Course.belongsTo(models.Subject);
        Course.belongsTo(models.School);
        Course.belongsTo(models.Person, { as: 'Teacher' });
      }
    }
  );
 return Course;
};

人员

module.exports = function(sequelize, DataTypes) {

  var Person = sequelize.define('Person', {
    ....
    },
    {
      associate: function(models){
        Person.belongsTo(models.Role, { as: 'Role' });
        Person.belongsTo(models.School, { as: 'School' });
        Person.belongsTo(models.Person, { as: 'Tutor' });
      }
    }
  );

  return Person;
};

和关联表注册

module.exports = function(sequelize, DataTypes) {

  var Enrollment = sequelize.define('Enrollment', {
      ....
    },
    {
      associate: function(models){
        Enrollment.belongsTo(models.Product, {as: 'Product'});
        Enrollment.belongsTo(models.School, { as: 'School' });

        models.Person.belongsToMany(models.Course, {through: {model: Enrollment},foreignKey: 'StudentEnrollId'});
        models.Course.belongsToMany(models.Person, {through: {model: Enrollment},foreignKey: 'CourseEnrollId'});

      }
    }

  );
  return Enrollment;
};

我尝试遵循以下"示例"，但除了解释简单的查询(其中包含贯穿参数)之外，并没有太多解释.

I tried following this "example" but doesn't explain much rather than a simple query where include the parameter through.

我要归档的是获取给定所有学生ID(人员模型)的所有课程.如您所见，课程模型仅保存一起构成课程的差异表的ID.人员模型还与不同模型相关联，因此我使用foreignKey: 'StudentEnrollId'给出了一个自定义ID名称，但是当我尝试在包含model : db.Person, as: 'StundetEnroll'中指定ID名称时，查询显示以下错误:Person (StudentEnroll) is not associated to Course

What I trying to archive is to get All the courses given a Student id (Person Model). As you can see the course model only saves the id of differents tables that together form a course. The Person Model also is associate to differents models so I give a custom id name with foreignKey: 'StudentEnrollId' but when I try to specify the id name in the include model : db.Person, as: 'StundetEnroll' the query show the following error: Person (StudentEnroll) is not associated to Course

推荐答案

您还需要在belongsToMany关联中定义别名as

You need to define the alias as also in the belongsToMany association

models.Person.belongsToMany(models.Course, { as: 'CourseEnrolls', through: { model: Enrollment }, foreignKey: 'StudentEnrollId'});
models.Course.belongsToMany(models.Person, { as: 'StudentEnrolls', through: { model: Enrollment }, foreignKey: 'CourseEnrollId'});

现在，您将可以查询所有学生的Course，反之亦然

Now you will be able to query Course with all it's students and vice-versa

models.Course.findByPrimary(1, {
    include: [
        {
            model: models.Person,
            as: 'StudentEnrolls'
        }
    ]
}).then(course => {
    // course.StudentEnrolls => array of Person instances (students of given course)
});

您还可以使用get/set Associations方法来检索或设置关联的对象

You can also use get/set Associations methods in order to retrieve or set associated objects

// assuming that course is an instance of Course model
course.getStudentEnrolls().then(students => {
    // here you get all students of given course
});

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