我有CRUD system
。这是我的create.js
文件。如何使db connection
可用于其余文件,而无需在每个文件中重写相同的代码。
mongo = require('mongodb').MongoClient
global.db = null
sDatabasePath = 'mongodb://localhost:27017/kea'
global.mongoId = require('mongodb').ObjectID
/**************************************************/
mongo.connect(sDatabasePath, (err, db) => {
if (err) {
console.log('ERROR 003 -> Cannot connect to the database')
return false
}
global.db = db
console.log('OK 002 -> Connected to the database')
var jStudent =
{
"firstName": "Sarah",
"lastName": "Jepsen",
"age": 27,
"courses": [
{
"courseName": "Web-development",
"teachers": [
{
"firstName": "Santiago",
"lastName": "Donoso"
}
]
},
{
"courseName": "Databases",
"teachers": [
{
"firstName": "Dany",
"lastName": "Kallas"
},
{
"firstName": "Rune",
"lastName": "Lyng"
}
]
},
{
"courseName": "Interface-Design",
"teachers": [
{
"firstName": "Roxana",
"lastName": "Stolniceanu"
}
]
}
]
}
global.db.collection('students').insertOne(jStudent, (err, result) => {
if (err) {
var jError = { "status": "error", "message": "ERROR -> create.js -> 001" }
console.log(jError)
}
var jOk = { "status": "ok", "message": "create.js -> saved -> 000" }
console.log(jOk)
console.log(JSON.stringify(result))
})
})
因为这不能自行解决。它说:Cannot read property 'collection' of undefined
,但我不想再重复一次sam代码。什么是solution
?
global.db.collection('students').find({}, { "courses.courseName": true, _id: false }).toArray((err, result) => {
if (err) {
var jError = { "status": "error", "message": "ERROR -> student.js -> 001" }
console.log(jError)
}
var jOk = { "status": "ok", "message": "student.js -> all courses found -> 000" }
console.log(jOk)
console.log(JSON.stringify(result))
})
答案 0 :(得分:0)
使用以下代码
为mongodb连接创建单独的文件// External Modules
// MongoDB connection
var mongoose = require( 'mongoose' );
var dbURI = '127.0.0.1:27017/kea';
mongoose.connect(dbURI);
// CONNECTION EVENTS
// When successfully connected
mongoose.connection.on('connected', function () {
console.log('Mongoose default connection open to ' + dbURI);
});
// If the connection throws an error
mongoose.connection.on('error',function (err) {
console.log('Mongoose default connection error: ' + err);
});
// When the connection is disconnected
mongoose.connection.on('disconnected', function () {
console.log('Mongoose default connection disconnected');
});
// If the Node process ends, close the Mongoose connection
process.on('SIGINT', function() {
mongoose.connection.close(function () {
console.log('Mongoose default connection disconnected through app
termination');
process.exit(0);
});
});
通过app.js将其提供给整个应用
var db = require('./server/models/mongodb');
它会做什么,它在app start上连接到mongodb。现在,您可以在应用程序的每个位置使用mongodb连接,而无需再次运行相同的连接命令。