Neither mongoose.connect('mongodb://localhost/sync-db'); nor mongoose.createConnection('mongodb://localhost/sync-db'); is creating the sync-db on local host.
Though both connection callbacks are successfully connected. But when I tried to check both robo-mongo and mongod client console using the command show dbs, the sync-db is neither to be seen on robo-mongo nor on mongod client
WTF?
Since no one is answering this question, I will post my own answer based on what #Odonno said on the comment, which is correct.
The codes above use to create database is not wrong, in the background the database has already been created, but for some reason (I hope someone will explain this) you wont see it until you added some data to it.
Related
Today i started migrating from firebase to mongoDB,
I used this tutorial and its all up and running http://thejackalofjavascript.com/re-architecting-a-firebase-app-in-node/
When checking the code i see there is a mongolab link connected to the code,
mongodb://admin:admin123#ds061620.mongolab.com:61620/testsync
My question is: can i easily setup my own local database to use instead of this? and what packages i would need to do this?
The main reason for switching to mongo instead of firebase is the pricing, please take this into account.
Yes, of course you can.
First, install mongodb locally, to do that, follow the instructions for the distribution you're working on.
Then, make sure your mongodb service is running.
After that, on your database connection script, change the connection parameters.
I guess that you have something like this on your .js file:
mongodb://admin:admin123#ds061620.mongolab.com:61620/testsync
Just to make a connection test, try to change it to:
mongo://localhost/test
After a successful connection, you can start to manage your database as you want.
As additional information, you don't have to specify user, password and a different port than the mongo's default, because you're using your local configuration, if you want to do so, you have to configure your mongodb server to make it work that way.
I'm working with mongoose ORM to manage a local database, and here's my connection function working.
Mongoose connection to local database
Hope this helps you.
It is possible to connect to a MongoDB cluster which currently does not have by setting "connectWithNoPrimary" to "true". Then, however, it will still be possible to read but not write. I need a way to know if that's the case in an Express middleware. Sadly did not find a way to do that.
I know there is "mongoose.connection.readyState" which tells me if the connection is ready is there something similar to know if I can write?
Thanks!
Problem essence
Writing the API server in NodeJS (Express) using the PostgreSQL database (connecting to it remotely through the service ElephantSQL and work through Sequelize). Today appeared an error "SequelizeHostNotFoundError". It occurs even in the checked endpoints.
Error text
(it remains only a screenshot of the error)
My attempts to solve the problem
Tried to perform a GET request to my API not via Postman and via the browser (did not help).
Tried to create a new DB on the same service ElephantSQL (didn't help, but migrations to create new tables and relationships somehow executed and endpoints still not working).
Tried to connect to the database directly via IDE DataGrip (connection test is successful and the database is loaded with all the tables).
What could be the problem ? On stackoverflow some wrote that the problem may occur due to the lack of a paid subscription to Google Cloude Functions, but I do not seem to use it. There is an option to connect to PostgreSQL locally, but I want to understand.
I am using MongoDB, so I am connecting trough MongoClient.connect
but I have to use that, for every route where I want to work with the database.
Tried to preload it to an object, but then the changes are not visible, till the server is restarted. Right now, it's working properly, I am only a bit worried about the performance.
Is there a better way to do that?
THe correct answer is "it depends".
For a simple desktop application where your NodeJS program is the only client: sure. A persistent connection is fine.
For an enterprise application with 100s or 1000s of concurrent users each connecting independently: no, you probably do NOT want to hold the connection open "forever".
One possible solution for the latter scenario is Connection Pooling.
You should only need to connect to your DB once - when the server starts. As long as the server is running, the connection should persist. There is no reason to connect multiple times.
Very simple and stupid question I came up with today when was playing around with sails and mongo db (adapter of the waterline odm). I just shut down the mongo while my sails server still has been running and saw nothing, neither in logs of sails or in the browser. How I could handle such situation?
If sails.js attempts a connection to the DB you will most certainly get a message in your console if the Mongo server is shut down, but if no request is made that requires a DB connection, then you will not see any error because no error as of yet exists.
It sounds like you might require a process that will monitor your DB and check to make sure it is still running? There are Sail.js options where you could create a CRON job to check the connection. Or you could use other application monitoring services like New Relic to monitor your DB.