MongoDB，如果新值不为null，则更新集合字段 [英] MongoDB, update collection field if new value is not null

问题描述

仅当新值不为null时，我才会更新设置值的集合。
我有这样的代码：

I would update a collection setting the value only if the new values are not null. I have a code like this:

 ...
 var userName = req.body.nome;
 var userSurname = req.body.cognome;
 var userAddress = req.body.indirizzo;

 collection.update(
     {_id:ObjectId(req.session.userID)},
     {$set: { nome: userName, cognome: userSurname, indirizzo: userAddress }}
 )

有没有一种简单的方法可以做到这一点？

Is there an easy way for doing this?

另一种方式：
如果我可以从表格的占位符中取值 req.body。* 数据，我可以解决问题..但这可能吗？

ANOTHER WAY: if I could take the value req.body.* from the placeholder of the form where I take the data, I could solve the problem.. but is this possible?

推荐答案

你可以尝试这样的事情：

You could try something like this:

var objForUpdate = {};

if (req.body.nome) objForUpdate.nome = req.body.nome;
if (req.body.cognome) objForUpdate.cognome = req.body.cognome;
if (req.body.indirizzo) objForUpdate.indirizzo = req.body.indirizzo;

//before edit- There is no need for creating a new variable
//var setObj = { $set: objForUpdate }

objForUpdate = { $set: objForUpdate }

collection.update({_id:ObjectId(req.session.userID)}, objForUpdate })

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