Question

我有2个架构：

var siteFeedbackSchema = new Schema({
    user: {type:Schema.ObjectId, ref: constants.DB_MODELS.USERS, required: true},
    comment: {type: String},
    __sv: {type: Number, default: SCHEMA_VERSION}
}, {strict: true, timestamps: { createdAt: 'created',  updatedAt: 'modified'}});

var usersSchema = new Schema({
    userName: {type: String, required: true},
    firstName: {type: String, required: true},
    lastName: {type: String, required: true},
    __sv: {type: Number, default: SCHEMA_VERSION}
}, {strict: true, timestamps: { createdAt: 'created',  updatedAt: 'modified'}});

我填充用户密钥，当我在/ sitefeedbackSchema上执行GET并返回doc：

{
"_id": "57850bd22e08cf206a3064e3"
"modified": "2016-07-12T15:25:06.652Z"
"created": "2016-07-12T15:25:06.652Z"
"comment": "good"
"user": {
    "_id": "5783cdcc20de829c5613a9a1"
    "modified": "2016-07-11T16:48:12.371Z"
    "created": "2016-07-11T16:48:12.371Z"
    "userName": "ramanr"
    "firstName": "rads"
    "lastName": "rrrr"
    "__v": 0
    "__sv": 1
}
"__v": 0
"__sv": 1
}

但是，我只希望从用户架构中显示userName。有没有办法选择我们想要的键？

{
"_id": "57850bd22e08cf206a3064e3"
"modified": "2016-07-12T15:25:06.652Z"
"created": "2016-07-12T15:25:06.652Z"
"comment": "good"
"user": {
    "userName": "ramanr"
      }
"__v": 0
"__sv": 1
}

是否有支持这个的cli？

Answer 1

看看预测。基本上MongoDB已经构建为每次检索完整的文档，但您可以使用投影来避免这种限制： https://docs.mongodb.com/manual/tutorial/project-fields-from-query-results/

Answer 2

如果您只想为填充的文档返回一些特定字段？这可以通过将通常的字段名称语法作为第二个参数传递给populate方法来实现。我假设你使用mongoose所以你可以使用像

fruit.Length >= index && fruit != "banana"

如何仅填充mongo中另一个模式内的模式对象中的选择键

2 个答案: