postgresql - 使用 n :m and 1:m associations and update Model 后续删除实例

Question

我的 postgresql 数据库中有 2 个模型并使用 sequelize 和节点:

1. 用户
2. 交易

并且是这样关联的:

UserModel.hasMany(TransactionModel, { as: 'sentTransactions', foreignKey: 'senderId' });
UserModel.hasMany(TransactionModel, { as: 'receivedTransactions', foreignKey: 'receiverId' });
UserModel.belongsToMany(TransactionModel, { as: 'transactionLikes', through: 'UserLike', foreignKey: 'userId' });
TransactionModel.belongsTo(UserModel, { as: 'receiver' });
TransactionModel.belongsTo(UserModel, { as: 'sender' });
TransactionModel.belongsToMany(UserModel, { as: 'likers', through: 'UserLike', foreignKey: 'transactionId' });

这意味着一个用户有很多接收和发送的交易，每个用户可以“喜欢”很多交易。

如何删除交易并删除所有关联(接收方、发送方、喜欢方)？我也不想删除用户。

我还想更新这样定义的用户模型，以添加“电子邮件”属性:

const UserModel = db.define('user', {
   id: { type: Sequelize.STRING, unique: true, primaryKey: true },
   firstName: { type: Sequelize.STRING  },
   lastName: { type: Sequelize.STRING },
   username: {
    type: Sequelize.STRING,
    unique: {
    args: true,
    msg: USERNAME_IS_TAKEN,
   },
 }

如何更新模型？现有实例会怎样？

预先感谢您的帮助!

Answer 1

根据 this tutorial你的 M:N 关系应该像你期望的那样开箱即用:

For n:m, the default for both is CASCADE. This means, that if you delete or update a row from one side of an n:m association, all the rows in the join table referencing that row will also be deleted or updated.

此外，要强制执行 CASCADE 行为，您还可以将 onDelete 选项传递给关联调用。像这样的东西应该可以解决问题:

TransactionModel.belongsToMany(UserModel, { as: 'likers', through: 'UserLike', foreignKey: 'transactionId', onDelete: 'CASCADE' });

向用户模型添加电子邮件属性应该就这么简单:

const UserModel = db.define('user', {
    id: {
        type: Sequelize.STRING,
        unique: true,
        primaryKey: true
    },
    firstName: { type: Sequelize.STRING  },
    lastName: { type: Sequelize.STRING },
    username: {
        type: Sequelize.STRING,
        unique: {
            args: true,
            msg: USERNAME_IS_TAKEN,
        }
    },
    email: { type: Sequelize.STRING }
});