[英]Auto incrementing sequence field error - MongoDB, Mongoose
我按照這個SO問題來生成貓鼬的自動遞增序列字段。
但是在實現和運行代碼時,出現以下錯誤:
TypeError: Cannot read property 'seq' of null
下面是我的代碼:
Counter.js文件
// app/models/counter.js
// load the things we need
var mongoose = require('mongoose');
// define the schema for our user model
var counterSchema = mongoose.Schema({
_id: {type: String, required: true},
seq: {type: Number, default: 0}
});
// methods ======================
// create the model for users and expose it to our app
module.exports = mongoose.model('Counter', counterSchema);
SupportTicket.js文件
var Counter = require('../models/counter');
var ticketSchema = mongoose.Schema({
issue: String,
ticketNo: Number,
dateCreated : { type: Date, default: Date.now }
});
ticketSchema.pre('save', function(next) {
var doc = this;
Counter.findByIdAndUpdate({_id: 'entityId'}, {$inc: { seq: 1}}, function(error, counter) {
if(error)
return next(error);
doc.ticketNo = counter.seq;
next();
});
});
我不知道為什么會收到“無法讀取null的'seq'屬性”的提示嗎?
counter.findByIdAndUpdate({_id: 'url_count'},
{$inc: {seq: 1} },
{upsert: true , new: true},
function(error, counter)
添加此行。它將正常工作。
{upsert: true , new: true}
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