使用nodejs往mongodb中插入数据时出错

Question

当我使用nodejs操作mongodb时，读取数据和更新数据都是正常的，就是在插入数据时，报错了，提示：
{ MongoError: Cannot read property 'maxBsonObjectSize' of null

at Function.MongoError.create (C:\Users\Administrator\AppData\Roaming\npm\node_modules\mongodb\node_modules\mongodb-core\lib\error.js:31:11)
at toError (C:\Users\Administrator\AppData\Roaming\npm\node_modules\mongodb\lib\utils.js:114:22)
at C:\Users\Administrator\AppData\Roaming\npm\node_modules\mongodb\lib\collection.js:656:23
at handleCallback (C:\Users\Administrator\AppData\Roaming\npm\node_modules\mongodb\lib\utils.js:96:12)
at resultHandler (C:\Users\Administrator\AppData\Roaming\npm\node_modules\mongodb\lib\bulk\ordered.js:429:14)
at C:\Users\Administrator\AppData\Roaming\npm\node_modules\mongodb\node_modules\mongodb-core\lib\wireprotocol\2_4_support.js:473:9
at _combinedTickCallback (internal/process/next_tick.js:67:7)
at process._tickCallback (internal/process/next_tick.js:98:9)

name: 'MongoError',
message: 'Cannot read property 'maxBsonObjectSize' of null',
driver: true,
code: 14,
index: 0,
errmsg: 'Cannot read property 'maxBsonObjectSize' of null',
getOperation: [Function],
toJSON: [Function],
toString: [Function] }
有哪位朋友遇到过这个问题吗？

Answer 1

这里的maxBsonObjectSize是不是数据库文档里的一个字段？如果是的话，就算你不想在maxBsonObjectSize插入值，在插入数据时也要给它一个空值，例如空字符串''，空数组[]等。

Answer 2

看看是不是在插入回调之前把关闭数据库链接关闭了。

MongoClient.connect(uri, function (err, db) {
    if (err) {
        throw err;
    } else {
        console.log("successfully connected to the database");

        // Insert document in MongoDb Collection
                var document = {title:'test',category:'node.js'}

                db.collection('tut').insert(document, function(err,records){
                        //if (err) throw err;
                        console.log('inserted record id: ' + records[0]._id);
                  });
    }
    // @Warning: 这里会出错！
    db.close();
});

db.close();应该放在插入的回调里。像这样：

MongoClient.connect(uri, function (err, db) {
    if (err) {
        throw err;
    } else {
        console.log("successfully connected to the database");

        // Insert document in MongoDb Collection
        var document = {title:'test',category:'node.js'}

        db.collection('tut').insert(document, function(err,records){
            //if (err) throw err;
            console.log('inserted record id: ' + records[0]._id);
            // ###像这样，放在会调里关闭连接
            db.close();
        });
    }
});