mongodb - 如何确保 mongoDB 中仅填充两个字段之一

Question

我正在使用 Mongoose 作为 ODM，并尝试为动物/宠物建模。在模型中，我有 2 个字段:父字段和庇护所。我想确保宠物属于一个人或一个庇护所，但不能同时属于两者。哪些限制可以让我做到这一点。

我的 JS 模型:-

const petSchema = mongoose.Schema({
    name: { 
        type: String,
        required: [true, "Pet must have a name."],
        trim: true
    },
    species: {
        type: String,
        required: [true, "Pet must have a species."]
    },
    parent: {
        type: mongoose.Schema.Types.ObjectId,
        ref: 'User'
    },
    shelter: {
        type: mongoose.Schema.Types.ObjectId,
        ref: 'Shelter'
    }
}

我对数据库及其术语不熟悉，如果有任何错误，请纠正我。谢谢。

Answer 1

您可以使用所需的函数来确定这一点，如下所示:

const petSchema = mongoose.Schema({
    name: { 
        type: String,
        required: [true, "Pet must have a name."],
        trim: true
    },
    species: {
        type: String,
        required: [true, "Pet must have a species."]
    },
    parent: {
        type: mongoose.Schema.Types.ObjectId,
        ref: 'User',
        required: function() {
          return !this.shelter;
        }
    },
    shelter: {
        type: mongoose.Schema.Types.ObjectId,
        ref: 'Shelter',
        required: function() {
          return !this.parent;
        }
    }
}