Javascript | Client Libraries

Introduction

JavaScript can be used to interact with Oracle databases via various client libraries. This tutorial demonstrates how to connect to Oracle, execute queries, and manage data using JavaScript.

Setting Up Environment

Ensure you have the necessary libraries installed:

// Install OracleDB library
npm install oracledb

Make sure Oracle Instant Client is installed and configured on your system.

Connecting to Oracle

Example code snippet to connect to Oracle:

const oracledb = require('oracledb');

async function connectToOracle() {
    try {
        // Create connection
        const connection = await oracledb.getConnection({
            user: 'username',
            password: 'password',
            connectString: 'localhost/XE'
        });
        
        console.log('Connected to Oracle Database');
        
        // Close connection
        await connection.close();
    } catch (error) {
        console.error('Error connecting to Oracle Database:', error);
    }
}

connectToOracle();

Replace 'username', 'password', and 'localhost/XE' with your actual credentials and database connection details.

Executing Queries

Performing SQL queries with JavaScript:

const oracledb = require('oracledb');

async function executeQuery() {
    let connection;
    try {
        // Get connection
        connection = await oracledb.getConnection({
            user: 'username',
            password: 'password',
            connectString: 'localhost/XE'
        });

        // Execute query
        const result = await connection.execute('SELECT * FROM employees');
        console.log('Query Result:', result.rows);
    } catch (error) {
        console.error('Error executing query:', error);
    } finally {
        // Release connection
        if (connection) {
            try {
                await connection.close();
            } catch (error) {
                console.error('Error closing connection:', error);
            }
        }
    }
}

executeQuery();

Managing Data

Inserting, updating, and deleting data:

const oracledb = require('oracledb');

async function manageData() {
    let connection;
    try {
        // Get connection
        connection = await oracledb.getConnection({
            user: 'username',
            password: 'password',
            connectString: 'localhost/XE'
        });

        // Insert data
        await connection.execute('INSERT INTO employees (id, name) VALUES (:1, :2)', [1, 'John Doe']);

        // Update data
        await connection.execute('UPDATE employees SET name = :1 WHERE id = :2', ['Jane Doe', 1]);

        // Delete data
        await connection.execute('DELETE FROM employees WHERE id = :1', [1]);
        
        console.log('Data management operations completed');
    } catch (error) {
        console.error('Error managing data:', error);
    } finally {
        // Release connection
        if (connection) {
            try {
                await connection.close();
            } catch (error) {
                console.error('Error closing connection:', error);
            }
        }
    }
}

manageData();

Conclusion

JavaScript offers powerful capabilities to interact with Oracle databases, allowing seamless integration for data manipulation and management. By following the steps and examples provided in this tutorial, you can effectively utilize JavaScript for Oracle database operations.