Sequelize查找belongsToMany Association-Java 学习之路

我有两个表之间的关联m：n，像这样的sequelize：

Course

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;
};

Person

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 Enrollment

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;
};

我试着遵循这个“example”，但没有解释太多而不是一个包含参数through的简单查询 .

我试图存档的是获得给出学生ID（人物模型）的所有课程 . 正如您所看到的，课程模型仅保存不同表格的ID，这些表格一起形成课程 . Person模型也与不同模型相关联，因此我给出了一个自定义id名称 foreignKey: 'StudentEnrollId' 但是当我尝试在include 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

1 回答

您还需要在 belongsToMany 关联中定义别名 as

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，您将能够与所有学生一起查询 Course ，反之亦然

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对象

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

回复于 2024-04-28T13:26:05+08:00

Sequelize查找belongsToMany Association

1 回答

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