Question

let UserSchema = new Schema({
created: {
    type: Date,
    default: Date.now,
    required: true
},
username: {
    type: String,
    unique: true,
    required: true
},
password: {
    type: String,
    required: true
},
role: {
    default: 'user',
    type: String, //we can consider using array of strings as in case user has several roles at the same time
    requierd: true
},
devices: [
    {
        id: '1',
        permissions:['start','stop']
    },

    {
        id: '2',
        permissions:['start','restart']
    }
]
});

当我在req.params.headers中收到新的{id：＆＃39; 2＆＃39;，权限：[＆＃39;停止＆＃39;]}时，如何在不重复的情况下推送它。我需要检查是否为：＆＃39; 2＆＃39;已存在或不存在，那么我检查是否存在[＆＃39;停止＆＃39;]存在，然后如果它不存在我应该将其推送到收集中。

Answer 1

如果要查找与id或权限匹配的任何对象，可以使用$或操作数执行此操作，如下所示：

return User.findOne({ $or:[ {'devices.id': idValue}, {'devices.permissions': permission}  ]}).exec()
.then(user => {
    if(user) {
        console.log("We don't have to push it");
    } else {
        console.log("We have to push it");
    }
});

Answer 2

您可以在declare -p foo declare -- foo="42" echo "$foo" 42条件下使用function resolveAfter1() { return new Promise(resolve => { var scoresFromDb = db.account.find({}, { username: 1, score: 1 }).toArray(function(err, result) { if (err) throw err; // return result; }) setTimeout(() => { resolve('resolved'); }, 1000); }); } async function asyncCall() { var result = await resolveAfter1(); console.log(result); // here's your result return result; } asyncCall().then(result => console.log(result)); // console.log(asyncCall());来查找内部对象。为避免在数组中添加重复键，您可以使用update

elemMatch

如何在mongoose中进行查询

2 个答案: