如何确保 mongoDB 中只填充了两个字段之一

Question

我正在使用 mongoose 作为 ODM 并尝试为 animal/pet 建模。在模型中，我有 2 个字段，parent 和 shelter。我想确保宠物属于一个人或一个收容所，但不能同时属于两者。哪些限制允许我这样做。

我在 JS 中的模型：-

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，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;
        }
    }
}

Answer 2

我最终在 mongoose 中使用了预验证中间件:-

petSchema.pre('validate', function (next) {
    if((this.parent && this.shelter) || (!this.parent && !this.shelter))
        return next(new Error("At least and Only one field(parent, shelter) should be populated"))
    next()
})

如何确保 mongoDB 中只填充了两个字段之一

How to make sure that only one of two fields are populated in mongoDB

mongodb

mongoose

model