June 2021
Intermediate to advanced
290 pages
9h 21m
Chinese
Content preview from Node与Express开发（第2版）
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138
｜
第
13
章
映射，只把需要的数据传给视图（根据需要转换，就像前面的
price
一样）。
MVC
架构的某些变体中引入了称为
视图模型
的第三个组件。视图模型基本
上是对一个模型（或多个模型）进行提取和转换，以便在视图中显示。我们
在这里做的工作就相当于即时创建一个视图模型。
我们已经做了很多工作，并成功地使用数据库存储了度假产品信息。但如果不能更新数
据，那么数据库就没有什么用。所以，现在把注意力转移到数据库更新上来。
13.3.9
更新数据
我们已经看到了如何新增数据（给度假产品集合增加了种子数据）以及如何更新数据（在
预订度假产品时会更新售出的商品数量），现在来看一个更复杂一些的场景，其更能体现
文档数据库的灵活性。
如果一款度假产品尚未上市，那么我们就显示一个链接，并邀请用户收取这个产品
再次上市的通知。让我们把这个功能串联起来。首先，创建模式和模型（
models/
vacationInSeasonListener.js
）：
const mongoose = require('mongoose')
const vacationInSeasonListenerSchema = mongoose.Schema({
email: String,
skus: [String],
})
const VacationInSeasonListener = mongoose.model('VacationInSeasonListener',
vacationInSeasonListenerSchema) ...
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