在 Mongoose 中为对象数组创建索引

Question

我有两个模型设置：

ShopsModel

var ShopsSchema = new mongoose.Schema({
  name: {
    type: String,
    required: true
  }
});

var ShopsModel = mongoose.model("Shops", ShopsSchema);

字段组模型

var FieldGroupsSchema = new mongoose.Schema({
  title: {
    type: String,
    required: true
  },
  fields: [{
    label: {
      type: String,
      required: true
    },
    handle: {
      type: String,
      required: true
    }
  }],
  shop: {
    type: mongoose.Schema.Types.ObjectId,
    ref: "Shops"
  }
});

var FieldGroupsModel = mongoose.model("FieldGroups", FieldGroupsSchema)

每个 FieldGroups 实例都有一个与之关联的 ShopsModel。

我需要为FieldGroupsModelfields[i].handle值创建一个索引，这个索引需要两条规则；它需要对每个 FieldGroupsModel 实例都是唯一的，因此该数据将无效：

{
  title: "Some field group title here",
  fields: [
    {
      label: "Some label 1"
      handle: "some-label-1"
    },
    {
      label: "Some label 1"
      handle: "some-label-1" // Error: `some-label-1` already exists as a value of `fields[i].handle`.
    }
  ],
  shop: {
    "$oid": "1"
  }
}

第二条规则是第一条规则应该只适用于共享相同shop 值的 FieldGroupsModel 实例。所以这个数据是无效的：

// First bit of data
{
  title: "Some field group title here",
  fields: [
    {
      label: "Some label 1"
      handle: "some-label-1"
    }
  ],
  shop: {
    "$oid": "1"
  }
}

// Second bit of data
{
  title: "Another field group title here",
  fields: [
    {
      label: "Some label 1"
      handle: "some-label-1" // Error: `some-label-1` already exists as a value of `fields[i].handle` of a document which shares the same `shop` value.
    }
  ],
  shop: {
    "$oid": "1"
  }
}

但是，这将是有效的：

// First bit of data
{
  title: "Some field group title here",
  fields: [
    {
      label: "Some label 1"
      handle: "some-label-1"
    }
  ],
  shop: {
    "$oid": "1"
  }
}

// Second bit of data
{
  title: "Another field group title here",
  fields: [
    {
      label: "Some label 1"
      handle: "some-label-1" // This is valid because there's no other documents with the same `shop` value with the same `fields[i].handle` value.
    }
  ],
  shop: {
    "$oid": "2"
  }
}

我对 Mongo 和 Mongoose 还很陌生，所以这里的任何帮助都会非常感谢！ :)

Answer 1

您在 Schema 对象上调用 index 方法来执行此操作，如 here 所示。对于您的情况，它将类似于：

FieldGroupsSchema.index({"shop": 1, "fields.handle": 1}, {unique: true});

请阅读有关 Compound Indexes 的 MongoDB 文档了解更多详细信息。