MongoDB节点本机驱动程序创建重复文档

Question

> db.people.find()
{ "firstname" : "Fred", "lastname" : "Flintstone", "_id" : ObjectId("52e55737ae49620000fd894e") }
{ "firstname" : "Fred", "lastname" : "Flintstone with a change", "_id" : "52e55737ae49620000fd894e" }

app.post("/contacts", function (req, res) {
  console.log("POST /contacts, req.body: " + JSON.stringify(req.body));

  db.collection("people").save(req.body, function (err, inserted) {
    if (err) {
      throw err;
    } else {
      console.dir("Successfully inserted/updated: " + JSON.stringify(inserted));
      res.send(inserted);
    }
  });
});

以下是运行时日志消息：

POST /contacts, req.body: {"firstname":"Fred","lastname":"Flintstone"}
'Successfully inserted/updated: {"firstname":"Fred","lastname":"Flintstone","_id":"52e55737ae49620000fd894e"}'
POST /contacts, req.body: {"firstname":"Fred","lastname":"Flintstone with a change","_id":"52e55737ae49620000fd894e"}
'Successfully inserted/updated: 1'

为什么我的第二个不更新现有的记录？驱动程序没有将_id值强制转换为objectid吗？

Answer 1

我不知道为什么要创建第二个文档，但为什么不使用update函数（也许与upsert操作符一起使用）？

更新操作的示例：

var query = { '_id': '52e55737ae49620000fd894e' };

db.collection('people').findOne(query, function (err, doc) {
    if (err) throw err;

    if (!doc) {
        return db.close();
    }

    doc['lastname'] = 'Flintstone with a change';

    db.collection('people').update(query, doc, function (err, updated) {
        if (err) throw err;

        console.dir('Successfully updated ' + updated + ' document!');

        return db.close();
    });
});

现在使用upsert操作符：

var query = { '_id': '52e55737ae49620000fd894e' };
var operator = { '$set': { 'lastname': 'Flintstone with a change' } };
var options = { 'upsert': true };

db.collection('people').update(query, operator, options, function (err, upserted) {
    if (err) throw err;

    console.dir('Successfully upserted ' + upserted + ' document!');

    return db.close();
});