如何使用Couchbase和Node.js SDK在存储桶中执行更新和删除操作

Question

I am moving from mongodb to Couchbase using Node.js. I want to perform the CRUD operations. Insert(create) and Get are working fine, but when I want to perform Update and Delete getting some error messages (Here update purpose using 'upsert','replace' are used) like:

TypeError: Cannot read property 'replace' of undefined

Here is code:

db.js

// Instantiate Couchbase and Ottoman
var couchbase=require('couchbase');
var ottoman=require('ottoman');
// Build my cluster object and open a new cluster
var myCluster = new couchbase.Cluster('localhost:8091');
var myBucket = myCluster.openBucket('default');
ottoman.bucket=myBucket;
require('./model/user');
ottoman.ensureIndices(function(){});

user.js

var db = require('./../db.js').myBucket;
var ottoman = require('ottoman');

var userMdl = ottoman.model('User', {
    firstName: {type:'string'},
    lastName: {type:'string'},
    created: {type: 'Date', default:function(){return new Date()}},
    email:'string',
    phone: 'string'
},{
    index: {
        findByID: {   
            by: '_id'
        },
    }

})  
module.exports = userMdl;

routes.js

 var bodyParser = require('body-parser');
    var db = require('../schema/db').myBucket;
    var user=require('../schema/model/user');
    var jsonParser = bodyParser.json();
    var urlencodedParser = bodyParser.urlencoded({ extended: false });

    module.exports = function (app) {
    // Delete a record
    app.post("/api/delete/:_id", function(req, res) {
        console.log("_id:"+req.params._id)
        if(!req.params._id) {
            return res.status(400).send({"status": "error", "message": "A document id is required"});
        }
        db.delete({_id:req.params._id}, function(error, result) {
            if(error) {
                return res.status(400).send(error);
            }
            res.send(result);
        });
    });

    app.post('/api/user/update/:id',function(req,res){
       db.replace(req.params.id,{firstName:"Mahesh"},function(err,result){
         if (err) {
            res.status = 400;
            res.send(err);
            return;
         }
         else {
           res.status = 202;
           res.send(result);  
          }
        })
      })
    }

I am stuck here from last two days.

Answer 1

You missed one argument although it can be optional.
From Couchbase Node.js SDK document , it have 4 arguments, but you have only 3.

db.replace(req.params.id,{firstName:"Mahesh"},function(err,result){
=>
db.replace(req.params.id,{firstName:"Mahesh"}, {}, function(err,result){

With 3rd argument of empty map may work properly, but notice that Couchbase uses optimistic locking , so you require "CAS" value for original document when you modify the original to get data integrity.

Answer 2

the line in db.js var ottoman = require('ottoman'); it's a constructor itself. Then you have two instances, and the error comes in user.js when you try to define a model, because node-ottoman needs a reference to the bucket.

You should assign the bucket in the user.js or reuse the ottoman object that you left in the db.js

model.js

    // Instantiate Couchbase and Ottoman

    var couchbase = require('couchbase');
    var ottoman = require('ottoman');

    // Build my cluster object and open a new cluster
    var myCluster = new couchbase.Cluster('localhost:8091');
    var myBucket = myCluster.openBucket('default');
    ottoman.bucket = myBucket;

    var userMdl = ottoman.model('User', {
        firstName: {type:'string'},
        lastName: {type:'string'},
        created: {type: 'Date', default:function(){return new Date()}},
        email:'string',
        phone: 'string'
    },{
        index: {
            findByID: {   
                by: '_id'
            },
        }

    }) ;

    // this line needs to be after you define the model
    ottoman.ensureIndices(function(){});

    module.exports = userMdl;
    model.exports = mybucket;

Answer 3

You can update Couchbase document using 2 ways 1st by upsert method and second by N1qlQuery

bucket.upsert('user', {'name': 'Jay'}, {'expiry': 1}, function(err){
    bucket.get('user', function(err, result) {
        console.log('Have item: %j', result.value);
    })
});

let query = N1qlQuery.fromString("UPDATE `"+BUCKETNAME+"` SET name='"+data.name+"'  where _id ='"+id+"'");
bucket.query(query,(error,result)=>{
    if(error){
        console.log(error);
    }
    console.log(result);
});

You can delete Couchbase document using 2 ways 1st is removed method and second by N1qlQuery

bucket.remove(id, function(error, result) {
    console.log("Deleted");
});

let query = N1qlQuery.fromString("DELETE FROM `"+BUCKETNAME+"` WHERE _id = '"+id+"'");
bucket.query(query,(error,result)=>{
    if(error){
        console.log(error);
    }
    console.log(result);
})