How nodejs implements database

Connecting to a database in Node.js requires choosing a database system (relational or non-relational) and then establishing a connection using a module specific to that type. Common modules include mysql (MySQL), pg (PostgreSQL), mongodb (MongoDB), and redis (Redis). After the connection is established, you can use query statements to retrieve data and update statements to modify the data. Finally, the connection must be closed when all operations are completed to release resources. Improve performance and security by following these best practices, such as using connection pooling, parameterized queries, and handling errors gracefully.

How to connect and use a database in Node.js

Node.js is a popular JavaScript runtime A real-time environment typically used for building web applications and APIs. To store and manage data, Node.js can connect to various database systems.

Choose a database system

• Relational database (RDBMS): For example, MySQL, PostgreSQL, suitable for structured data and relationships Inquire.
• Non-relational database (NoSQL): For example, MongoDB, Redis, suitable for unstructured data and key-value storage.
• Cloud database: For example, AWS DynamoDB and Google Cloud Spanner provide scalable and high-availability database solutions.

Establishing a connection

Node.js has a variety of modules for interacting with databases. The following are common modules for each database type:

• MySQL: mysql or mysql2
• PostgreSQL: pg
• MongoDB: mongodb
• Redis: redis

To establish a connection, you can use the following code template:

const { createConnection } = require('mysql');

const conn = createConnection({
  host: 'localhost',
  port: 3306,
  user: 'root',
  password: '',
  database: 'mydb'
});

Query and update data

Once the connection is established , you can query and update data in the database. The following is a code sample for the query:

conn.query('SELECT * FROM users WHERE username = ?', ['jdoe'], (err, rows) => {
  if (err) throw err;

  console.log(rows);
});

To update the data, you can use the following code sample:

conn.query('UPDATE users SET email = ? WHERE username = ?', ['new@email.com', 'jdoe'], (err, result) => {
  if (err) throw err;

  console.log(result.affectedRows);
});

Close the connection

After completing all database operations , the connection should be closed to release resources. Here's how to close a MySQL connection:

conn.end();

Best Practices

• Use connection pooling to improve performance and scalability.
• Use SQL parameterized queries to prevent SQL injection attacks.
• Handle errors gracefully and implement appropriate error handling for asynchronous queries.
• Follow database best practices such as using appropriate indexing and normalization.

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