续集模型参考与关联 [英] Sequelize model references vs associations

问题描述

刚开始使用 Sequelize，我已经设置了一堆模型和种子，但我无法弄清楚引用与关联.如果他们甚至按照我的想法去做，我看不到参考的用例，但我在文档中找不到很好的解释.

Just starting to use Sequelize and I've setup a bunch of models and seeds, but I can't figure out references vs associations. I don't see the use case for references if they even do what I think they do, but I couldn't find a good explanation in the docs.

这是多余的引用和关联吗?

Is this redundant having references and associations?

module.exports = (sequelize, DataTypes) => {
  const UserTask = sequelize.define('UserTask',
    {
      id: {
        primaryKey: true,
        type: DataTypes.UUID,
        defaultValue: DataTypes.UUIDV4
      },
      userId: {
        type: DataTypes.UUID,
        references: { // <--- is this redundant to associate
          model: 'User',
          key: 'id'
        }
      }
      // ... removed for brevity
    },
    {
      classMethods: {
        associate: models => { <--- makes references redundant?
          UserTask.belongsTo(models.User, {
            onDelete: 'CASCADE',
            foreignKey: {
              fieldName: 'userId',
              allowNull: true,
              require: true
            },
            targetKey: 'id'
          });
        }
      }
    }
  );
  return UserTask;
};

推荐答案

使用 references 您可以创建对另一个表的引用，而无需添加任何约束或关联.这意味着这只是向数据库通知此表引用另一个数据库的一种方式.

Using references you create a reference to another table, without adding any constraints, or associations. Which means that is just a way of signaling the database that this table has a reference to another.

创建 association 将为属性添加外键约束.您可以执行关联功能背后的所有魔法.即 User.getTasks();

Creating an association will add a foreign key constraint to the attributes. And the you can perform all the magic behind it the association functions. i.e User.getTasks();

有关 references 的更多信息:https://sequelize.readthedocs.io/en/latest/docs/associations/#foreign-keys_1

关于 association 此处:http://docs.sequelizejs.com/manual/tutorial/associations.html

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