Connect from Node.js App

Node.js developers can connect to SkySQL through a native MariaDB Connector. Using MariaDB Connector/Node.js you can connect to SkySQL to use and administer databases from within your Node.js application.

Install MariaDB Connector/Node.js

MariaDB Connector/Node.js is usually installed either from the Node.js repository or manually from the source code package.

Install MariaDB Connector/Node.js via Repository

To install MariaDB Connector/Node.js from the Node.js repository, use NPM:

npm install mariadb

NPM connects to the Node.js repository and downloads MariaDB Connector/Node.js and all relevant dependencies into the node_modules/ directory.

Install MariaDB Connector/Node.js via Source Code

To download and install the MariaDB Connector/Node.js manually from source code:

Go to the MariaDB Connectors download page:
- https://mariadb.com/downloads/connectors/connectors-data-access/nodejs-connector
In the "Product" dropdown, select the Node.js connector.
Click the "Download" button to download the source code package
When the source code package finishes downloading, install it with NPM:

$ npm install mariadb-connector-nodejs-*.tar.gz

NPM untars the download and installs MariaDB Connector/Node.js in the node_modules/ directory.

Connect with MariaDB Connector/Node.js (Callback API)

Node.js developers can use MariaDB Connector/Node.js to establish client connections with SkySQL.

Require Callback API

MariaDB Connector/Node.js provides two different connection implementations: one built on the Promise API and the other built on the Callback API.

To use the Callback API, use the following module:

const** mariadb = require**(**'mariadb/callback'**);

Connect

createConnection(options) -> Connection

is the base function used to create a Connection object.

The createConnection(options) function returns a Connection object.

Determine the connection information for your SkySQL database service:

Option	Description
host	The fully Qualified Domain Name from the "Connect" window in SkySQL portal
port	The Read-Write Port or Read-Only Port from the "Connect" window in SkySQL portal
user	The desired username, which might be the default username in the Service Credentials view
password	The user's password, which might be the default password in the Service Credentials view if it was not yet customized
database	Database name to establish a connection to. No default is configured.
connectTimeout	Connection timeout in milliseconds. In Connector/Node.js 2.5.6, the default value changed to 1000. The default value for earlier versions is 10000.
rowsAsArray	A boolean value to indicate whether to return result sets as arrays instead of the default JSON. Arrays are comparatively faster.

Code Example: Connect

The following code example connects using the database and user account created in the example setup:

const mariadb = require('mariadb/callback');

// Certificate Authority (CA)",
var serverCert = [fs.readFileSync(process.env.SKYSQL_CA_PEM, "utf8")];

// Declare async function
function main() {
   let conn;

   try {
      conn = mariadb.createConnection({
         host: "example.skysql.com",
         port: 5009,
         ssl: { ca: serverCert },
         user: "db_user",
         password: "db_user_password",
         database: "test",
      });

      // Use Connection
      // ...
   } catch (err) {
      // Manage Errors
      console.log("SQL error in establishing a connection: ", err);
   } finally {
      // Close Connection
      if (conn) conn.end(err => {if(err){
         console.log("SQL error in closing a connection: ", err);}
      });
   }
}

main();

A try...catch...finally statement is used for exception handling.
New connections are created in auto-commit mode by default.
When you are done with a connection, close it to free resources. Close the connection using the connection.end([callback]) function.
The script calls the connection.end([callback]) function to close/end the connection in the finally block after the queries that are running have completed.
The end() function takes a callback function that defines one implicit argument for the Error object if thrown in closing the connection as argument. If no error is generated in closing a connection the Error object is null.

Connect with MariaDB Connector/Node.js (Promise API)

Node.js developers can use MariaDB Connector/Node.js to establish client connections with SkySQL.

Require Promise API

MariaDB Connector/Node.js provides two different connection implementations: one built on the Promise API and the other built on the Callback API. Promise is the default.

To use the Promise API, use the mariadb module:

const** mariadb = require**(**'mariadb'**);

Connect

createConnection(options) -> Promise is the base function used to create a Connection object.

The createConnection(options) returns a Promise that resolves to a Connection object if no error occurs, and rejects with an Error object if an error occurs.

Determine the connection information for your SkySQL database service:

Option	Description
host	The fully Qualified Domain Name from the "Connect" window in SkySQL portal
port	The Read-Write Port or Read-Only Port from the "Connect" window in SkySQL portal
user	The desired username, which might be the default username in the Service Credentials view
password	The user's password, which might be the default password in the Service Credentials view if it was not yet customized
database	Database name to establish a connection to. No default is configured.
connectTimeout	Connection timeout in milliseconds. In Connector/Node.js 2.5.6, the default value changed to 1000. The default value for earlier versions is 10000.
rowsAsArray	A boolean value to indicate whether to return result sets as arrays instead of the default JSON. Arrays are comparatively faster.

Create a file named .env to store your database credentials:

MDB_HOST = 192.0.2.50
MDB_PORT = 3306
MDB_USER = db_user
MDB_PASS = db_user_password
MDB_HOST = example.skysql.com
MDB_PORT = 5001
MDB_CA_PEM = /path/to/skysql_chain.pem
MDB_USER = db_user
MDB_PASS = db_user_password

Code Example: Connect

The following code example connects using the database and user account created in Setup for Examples:

// Required Modules
const fs = require("fs");
const mariadb = require("mariadb");
require("dotenv").config()

// Certificate Authority (CA)
const serverCert = [fs.readFileSync(process.env.MDB_CA_PEM, "utf8")];

// Declare async function
async function main() {
   let conn;

   try {
      conn = await mariadb.createConnection({
         host: process.env.MDB_HOST,
         port: process.env.MDB_PORT,
         user: process.env.MDB_USER,
         password: process.env.MDB_PASS,
         ssl: { ca: serverCert },
         database: "test",
      });

      // Use Connection
      // ...
   } catch (err) {
      // Manage Errors
      console.log("SQL error in establishing a connection: ", err);
   } finally {
      // Close Connection
      if (conn) conn.close();
   }
}

main();

Load the mariadb module using the require() function.
Declare an async function called main() using the async keyword.
An async function provides asynchronous, Promise-based code behavior.
Async functions may declare await expressions using the await keyword.
Await expressions yield control to a promise-based asynchronous operation.
Await expressions resume control after the awaited operation is either fulfilled or rejected.
The return value of an await expression is the resolved value of the Promise.
The async function name main is arbitrary and does not have special meaning as in some other programming languages.
Declare a variable called conn for the connection to be created using a let statement with the async function main.
A try...catch...finally statement is used for exception handling.
New connections are by default created in auto-commit mode.
In the try block, create a new connection using the mariadb#createConnection(options) function in the Promise API.
Send error messages if any to the console in the catch block.
When you are done with a connection, close it to free resources. Close the connection using the close() function.