我是 mongodb 的新手，我正在使用 mongoose 来验证和排序数据(如果这不起作用，我愿意将其更改为 MySQL)。
该应用程序将是一个电子商店，用于购买与电影、游戏等相关的商品。

我的架构如下:

var productSchema = {
    id: {
        type: String,
        required: true
    },
    name: {
        type: String,
        required: true
    },
    img: {
        type: String,
        required: true
    },
    price: {
        type: Number,
        required: true
    },
    stock: {
        type: Number,
        required: true
    },
    category: {
        object: {
            type: String,
            required: true
        },
        group: {
            type: String,
            required: true  
        },
        name: {
            type: String,
            required: true
        }
    }
};

最佳答案

您基本上是在寻找 "pre" middleware通过在集合中创建新文档来触发“保存”事件。这将检查当前文档内容并从值中提取“字符串”，以便为 _id 创建“前缀”值。 .

还有另一部分，当该特定“前缀”已经存在一个值以使其不同时，“前缀”需要添加数字计数器。 MongoDB 中有一个常用技术用于 "Generate an auto-incrementing sequence field" ，这基本上涉及保留一个“计数器”集合并在每次访问它时递增该值。

作为一个完整且独立的演示，您可以按如下方式组合这些技术:

var async = require('async'),
    mongoose = require('mongoose'),
    Schema = mongoose.Schema;

mongoose.connect('mongodb://localhost/warehouse');

var counterSchema = new Schema({
  "type": { "type": String, "required": true },
  "prefix": { "type": String, "required": true },
  "counter": Number
});

counterSchema.index({ "type": 1, "prefix": 1 },{ "unique": true });

counterSchema.virtual('nextId').get(function() {
  return this.prefix + this.counter;
});

var productSchema = new Schema({
  "_id": "String",
  "category": {
    "object": { "type": String, "required": true },
    "group": { "type": String, "required": true },
    "name": { "type": String, "required": true }
  }
},{ "_id": false });

productSchema.pre('save', function(next) {
  var self = this;

  if ( !self.hasOwnProperty("_id") ) {

    var prefix = self.category.object.substr(0,1).toUpperCase()
      + self.category.group.substr(0,1).toUpperCase()
      + self.category.name.split(" ").map(function(word) {
        return word.substr(0,1).toUpperCase();
      }).join("");

    mongoose.model('Counter').findOneAndUpdate(
      { "type": "product", "prefix": prefix },
      { "$inc": { "counter": 1 } },
      { "new": true, "upsert": true },
      function(err,counter) {
        self._id = counter.nextId;
        next(err);
      }
    );
  } else  {
    next();  // Just skip when _id is already there
  }
});

var Product = mongoose.model('Product',productSchema),
    Counter = mongoose.model('Counter', counterSchema);

async.series(
  [
    // Clean data
    function(callback) {
      async.each([Product,Counter],function(model,callback) {
        model.remove({},callback);
      },callback);
    },
    function(callback) {
      async.each(
        [
          {
            "category": {
              "object": "ring",
              "group": "movies",
              "name": "lord of the rings"
            }
          },
          {
            "category": {
              "object": "ring",
              "group": "movies",
              "name": "four weddings and a funeral"
            }
          },
          {
            "category": {
              "object": "ring",
              "group": "movies",
              "name": "lord of the rings"
            }
          }
        ],
        function(data,callback) {
          Product.create(data,callback)
        },
        callback
      )
    },
    function(callback) {
      Product.find().exec(function(err,products) {
        console.log(products);
        callback(err);
      });
    },
    function(callback) {
      Counter.find().exec(function(err,counters) {
        console.log(counters);
        callback(err);
      });
    }
  ],
  function(err) {
    if (err) throw err;
    mongoose.disconnect();
  }
)

[ { category: { name: 'lord of the rings', group: 'movies', object: 'ring' },
    __v: 0,
    _id: 'RMLOTR1' },
  { category:
     { name: 'four weddings and a funeral',
       group: 'movies',
       object: 'ring' },
    __v: 0,
    _id: 'RMFWAAF1' },
  { category: { name: 'lord of the rings', group: 'movies', object: 'ring' },
    __v: 0,
    _id: 'RMLOTR2' } ]
[ { __v: 0,
    counter: 2,
    type: 'product',
    prefix: 'RMLOTR',
    _id: 57104cdaa774fcc73c1df0e8 },
  { __v: 0,
    counter: 1,
    type: 'product',
    prefix: 'RMFWAAF',
    _id: 57104cdaa774fcc73c1df0e9 } ]

关于javascript - 使用其他字段的数据创建 ID，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/36629147/