Develop Reference

NESTJS AWS Lambda & Sequelize connection pool

Since I have given the pool parameters as mentioned in the below code snippet, Is necessary to close the connection after each lambda invocation?
This aws lambda function is supposed to be triggered every minute, is the pool parameter only enough to close the connection?
export const databaseProviders = [
{
provide: 'vendorDB',
useFactory: async (awsSecrets: AwsSecretsService) => {
const { host, port, username, password, database } =
await awsSecrets.getVendorDbConfig();
const sequelize = new Sequelize({
dialect: 'postgres',
host,
port,
username,
password,
database,
logging: true,
pool: {
max: 1,
min: 0,
idle: 1000,
},
});
sequelize.addModels([VendorEntity]);
// await sequelize.sync();
return sequelize;
},
inject: [AwsSecretsService],
},

How to connect to mysql server with electron?

I'm trying to connect my electron app to a database, but I keep getting the same error
ETIMEOUT
or that the user don't have access
But if I try with my local database works fine, any ideas of why is this happening?
var mysql = require('mysql');
// Add the credentials to access your database
var connection = mysql.createConnection({
host : 'xxx.xxx.xxx',
user : 'xxxxx',
password : 'xxxxxxx',
database : 'xxxxx',
pool: {
max: 1000,
min: 0,
idleTimeoutMillis: 30000000
},
options: {
"enableArithAbort": false,
"encrypt": false
},
debug: true
});
// connect to mysql
connection.connect(function(err) {
if(err){
console.log(err.code);
console.log(err.fatal);
} else {
console.log("OK");
}
});

Can't create table in database using class model in Sequelize

I'm using node.js with express and sequelize and my DB is mysql.
I tried to create a class model as written in the documentation: https://sequelize.org/master/manual/model-basics.html. I was able to connect to the DB, but couldn't figure out how to sync the model with the DB in order to create tables. here is my user model:
const { DataTypes, Model } = require('sequelize');
const connection = require("../server");
export class User extends Model { }
User.init({
id: {
type: DataTypes.BIGINT,
autoIncrement: true,
primaryKey: true,
unique: true,
allowNull: false
},
username: {
type: DataTypes.STRING,
allowNull: false,
unique: true,
},
password: {
type: DataTypes.STRING,
allowNull: false,
},
userType: {
type: DataTypes.STRING,
allowNull: false,
}
}, {
connection
});
and here is my server.js:
const express = require("express");
const Sequelize = require("sequelize");
const app = express();
const port = 8080;
const connection = new Sequelize("coupons2", "root", "1234", {
host: "localhost",
dialect: "mysql"
})
connection.sync()
.then(() => {
console.log("Connection to DB was successful");
})
.catch(err => {
console.error("Unable to connect to DB", err);
});
app.listen(port, () => {
console.log(`Server is running on port ${port}`);
})
module.exports = connection;
Thank you!

I think you forgot to require the Sequelize as shown in document you mentioned above
`const {Sequelize, DataTypes, Model } = require('sequelize');
and if you want that it table create automatically by models you can use sequelize.sync in your project
await sequelize.sync({ force: true });
console.log("All models were synchronized successfully.");

User.sync() - creates the table if it doesn't exist (and does nothing if it already exists)
User.sync({ force: true }) - creates the table, dropping it first if it already existed
User.sync({ alter: true }) - checks what is the current state of the table in the database (which columns it has, what are their data types, etc), and then performs the necessary changes in the table to make it match the model.
(async () => {
await sequelize.sync({ alter: true });
})();

I managed to create tables by importing the models to my server.js:
const models = require("./src/models/index");, and using the sync() method.

Connection Pooling in Nodejs (Using sequelize)

I write the code below. According to my understanding the "max:" in pool shows the max number of connection we can create in pool. So if I set the value of max as 0. Then it should not established any connection. I just want to clarify this.
var sequelize = new Sequelize(
process.env.DATABASE_NAME,
process.env.DATABASE_USERNAME,
process.env.DATABASE_PASSWORD, {
pool:{
max: 0,
min: 0,
idle: 10000,
acquire:30000
},
logging: console.log("connection created"),
host: process.env.DATABASE_HOST,
dialect: 'mysql',
operatorsAliases: false
}
);

I have no idea about Sequelize but simply we can create a connection this way.I think this will be little bit helpful for you.
/**
* create connection pool
*/
var con = mysql.createPool({
connectionLimit: 100000,
host: 'enter host',
user: process.env.DATABASE_USERNAME,
password: process.env.DATABASE_PASSWORD,
database: process.env.DATABASE_NAME
});
con.getConnection(async function(err, connection) {
let result=connection.query('SELECT * FROM table_name');
console.log(result);
if(err) throw err;
})

what's wrong with the way they have it set up in their examples exactly?
const sequelize = new Sequelize(config.db.uri, {
pool: {
max: 100,
min: 0,
idle: 10000,
},
dialectOptions: {
ssl: config.db.ssl,
},
// logging: logger.debug.bind(logger),
});
the models utilize it on their own... what am i missing here?

For "sequelize": "^5.21.3", you can't set pool.max to 0 anymore. If you do this, sequelize will throw an error:
max must be an integer > 0

Connect multiple database in mongoDb using Nodejs runtime

I am trying to connect the multiple database with the API request. I tried to connect the DB using this code:
const connectionString = `mongodb+srv://${process.env.DB_HOST}/${company.dbName}`;
const client = new MongoClient(connectionString, {
autoReconnect: true,
reconnectTries: 60,
reconnectInterval: 10000,
useNewUrlParser: true,
auth: {
user: process.env.DB_USER,
password: process.env.DB_PASS
}
});
await client.connect();
await client.db(company.dbName);
I didn't achieve any solution with the mentioned code.
Looking for the good solution :)