MariaDB Connector/Node.js (Promise API) Examples
This page is part of MariaDB's Documentation.
The parent of this page is: MariaDB Connector/Node.js with Promise API
Topics on this page:
Overview
Example programs provided here illustrate how to use MariaDB Connector/Node.js to connect to MariaDB database products and retrieve and manipulate data.
Short Example
The following example uses the Promise API to select data from the table defined in Setup for Examples. Complete information on using Connector/Node.js with Promise API is available.
const mariadb = require("mariadb");
// Main function
async function main() {
let conn;
try {
conn = await mariadb.createConnection({
host: "192.0.2.50",
user: "db_user",
password: "db_user_password",
database: "test",
});
// Use Connection to get contacts data
var rows = await get_contacts(conn);
//Print list of contacts
for (i = 0, len = rows.length; i < len; i++) {
console.log(`${rows[i].first_name} ${rows[i].last_name} <${rows[i].email}>`);
}
} catch (err) {
// Manage Errors
console.log(err);
} finally {
// Close Connection
if (conn) conn.close();
}
}
//Get list of contacts
function get_contacts(conn) {
return conn.query("SELECT first_name, last_name, email FROM test.contacts");
}
main();
Example output:
John Smith <john.smith@example.com>
Long Example
The following example program connects using query pipelining, and demonstrates CRUD (CREATE, READ, UPDATE, DELETE) operations within a transaction, including a batch operation, with the example setup.
const mariadb = require("mariadb");
// Main Function
async function main() {
let conn;
try {
// Establish Connection (with query pipelining set)
conn = await mariadb.createConnection({
host: "192.0.2.50",
user: "db_user",
password: "db_user_password",
database: "test",
pipelining: true,
});
var contacts = [
["John", "Smith", "johnsmith@example.com"],
["Jon", "Smith", "jon.smith@example.com"],
["Johnny", "Smith", "johnny.smith@example.com"],
];
const updateContact = {
first_name: "John",
email: "john.smith@example.com",
};
const deleteContact = {
id: 3
};
await crudInPipeline(conn, contacts, updateContact, deleteContact);
} catch (err) {
// Manage Errors
console.error("Error connecting to the database with pipeline: ", err);
} finally {
// Close Connection
if (conn) conn.close();
}
}
async function crudInPipeline(conn, data, update, del) {
try {
// Start Transaction
await conn.beginTransaction();
try {
//Drop Table IF Exists
await conn.query("DROP TABLE IF EXISTS test.contacts");
//Create Table
await conn.query("CREATE TABLE IF NOT EXISTS test.contacts (id INT PRIMARY KEY AUTO_INCREMENT,first_name VARCHAR(25),last_name VARCHAR(25),email VARCHAR(100)) ENGINE=InnoDB");
// Add Contacts in Batch
await conn.batch(
"INSERT INTO test.contacts(first_name, last_name, email) VALUES(?, ?, ?)",
data
);
// Update
await conn.query(
"UPDATE test.contacts SET email = ? WHERE first_name = ?",
[update.email, update.first_name]
);
// Delete
await conn.query(
"DELETE FROM test.contacts WHERE id = ?",
[del.id]
);
// Commit Changes
await conn.commit();
//Select data
var rows = await conn.query("SELECT first_name, last_name, email FROM test.contacts");
//Print list of contacts
for (i = 0, len = rows.length; i < len; i++) {
console.log(`${rows[i].first_name} ${rows[i].last_name} <${rows[i].email}>`);
}
} catch (err) {
console.error("Error adding user, reverting changes: ", err);
await conn.rollback();
}
} catch (err) {
console.error("Error starting a transaction: ", err);
}
return Promise.resolve(1);
}
main();
Example output:
John Smith <john.smith@example.com>
Jon Smith <jon.smith@example.com>