Build a Node.js application
Install the Yugabyte Node.js Driver for YCQL
To install the YugabyteDB Node.js driver for YCQL, run the following command:
$ npm install yb-ycql-driver
Create the sample Node.js application
Prerequisites
This tutorial assumes that you have:
- installed YugabyteDB and created a cluster. Refer to Quick start.
- installed a recent version of Node.js.
- installed the async utility to work with asynchronous Javascript.
To install the async utility, run the following command:
$ npm install --save async
Write the sample Node.js application
Create a file yb-cql-helloworld.js and add the following content to it.
const ycql = require('yb-ycql-driver');
const async = require('async');
const assert = require('assert');
// Create a YB CQL client.
// DataStax Nodejs 4.0 loadbalancing default is TokenAwarePolicy with child DCAwareRoundRobinPolicy
// Need to provide localDataCenter option below or switch to RoundRobinPolicy
const loadBalancingPolicy = new ycql.policies.loadBalancing.RoundRobinPolicy ();
const client = new ycql.Client({ contactPoints: ['127.0.0.1'], policies : { loadBalancing : loadBalancingPolicy }});
async.series([
function connect(next) {
client.connect(next);
},
function createKeyspace(next) {
console.log('Creating keyspace ybdemo');
client.execute('CREATE KEYSPACE IF NOT EXISTS ybdemo;', next);
},
function createTable(next) {
// The create table statement.
const create_table = 'CREATE TABLE IF NOT EXISTS ybdemo.employee (id int PRIMARY KEY, ' +
'name varchar, ' +
'age int, ' +
'language varchar, ' +
'location jsonb);';
// Create the table.
console.log('Creating table employee');
client.execute(create_table, next);
},
function insert(next) {
// Create a variable with the insert statement.
const insert = "INSERT INTO ybdemo.employee (id, name, age, language, location) " +
"VALUES (1, 'John', 35, 'NodeJS', '{ \"city\": \"San Francisco\", \"state\": \"California\", \"lat\": 37.77, \"long\": 122.42 }');";
// Insert a row with the employee data.
console.log('Inserting row with: %s', insert)
client.execute(insert, next);
},
function select(next) {
// Query the row for employee id 1 and print the results to the console.
const select = 'SELECT name, age, language, location FROM ybdemo.employee WHERE id = 1;';
client.execute(select, function (err, result) {
if (err) return next(err);
var row = result.first();
const city = row.location.city;
console.log('Query for id=1 returned: name=%s, age=%d, language=%s, city=%s',
row.name, row.age, row.language, city);
next();
});
}
], function (err) {
if (err) {
console.error('There was an error', err.message, err.stack);
}
console.log('Shutting down');
client.shutdown();
});
Run the application
To use the application, run the following command:
$ node yb-cql-helloworld.js
You should see the following output.
Creating keyspace ybdemo
Creating table employee
Inserting row with: INSERT INTO ybdemo.employee (id, name, age, language) VALUES (1, 'John', 35, 'NodeJS');
Query for id=1 returned: name=John, age=35, language=NodeJS
Shutting down