問題描述

是否可以使用 Sequelize 在 MySQL 表上創(chuàng)建一個列，該列在創(chuàng)建新行時可以初始化，但永遠不會更新?

Is it possible to create a column on a MySQL table using Sequelize that can be initialized when creating a new row, but never updated?

例如，REST 服務(wù)允許用戶更新其個人資料.他可以更改除id 以外的任何字段.我可以從 API 路由上的請求中去除 id ，但這有點多余，因為有許多不同的模型表現(xiàn)相似.理想情況下，我希望能夠在 Sequelize 中定義一個約束，以防止將 id 列設(shè)置為 DEFAULT 以外的任何內(nèi)容.

For example, a REST service allows a user to update his profile. He can change any field except his id. I can strip the id from the request on the API route, but that's a little redundant because there are a number of different models that behave similarly. Ideally, I'd like to be able to define a constraint in Sequelize that prevents the id column from being set to anything other than DEFAULT.

目前，我正在使用 setterMethod 作為 id 來手動拋出 ValidationError，但這似乎是 hackish，所以我想知道如果有更干凈的方法來做到這一點.更糟糕的是，這個實現(xiàn)仍然允許在創(chuàng)建新記錄時設(shè)置 id，但我不知道如何解決這個問題，因為當(dāng) Sequelize 生成它調(diào)用 setterMethods.id 的查詢時 將值設(shè)置為 DEFAULT.

Currently, I'm using a setterMethod for the id to manually throw a ValidationError, but this seems hackish, so I was wondering if there's a cleaner way of doing this. Even worse is that this implementation still allows the id to be set when creating a new record, but I don't know a way around this as when Sequelize generates the query it calls setterMethods.id to set the value to DEFAULT.

return sequelize.define('Foo',
    {
        title: {
            type: DataTypes.STRING,
            allowNull: false,
            unique: true,
            validate: {
                notEmpty: true
            }
        }
    },
    {
        setterMethods: {
            id: function (value) {
                if (!this.isNewRecord) {
                    throw new sequelize.ValidationError(null, [
                        new sequelize.ValidationErrorItem('readonly', 'id may not be set', 'id', value)
                    ]);
                }
            }
        }
    }
);

推薦答案

看看這個 Sequelize 插件:

Look at this Sequelize plugin:

https://www.npmjs.com/package/sequelize-noupdate-attributes

它增加了對 Sequelize 模型中無更新和只讀屬性的支持.

It adds support for no update and read-only attributes in Sequelize models.

在您的特定情況下，您可以使用以下標(biāo)志配置屬性:

In your specific case, you could configure the attribute with the following flags:

{
  title: {
    type: DataTypes.STRING,
    allowNull: false,
    unique   : true,
    noUpdate : true
  }
}

這將允許 title 屬性的初始設(shè)置為空，然后一旦設(shè)置就阻止任何進一步的修改.

That will allow the initial set of the title attribute if is null, and then prevent any further modifications once is already set.

免責(zé)聲明:我是插件作者.

這篇關(guān)于無法更新的 Sequelize 列的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網(wǎng)！