How do I use Knex.js for database queries in Node.js?

How do I use Knex.js for database queries in Node.js?

Knex.js is a SQL query builder for Node.js. You can use it to build queries for various databases like PostgreSQL, MySQL, and SQLite.

Can you show me an example of a simple SELECT query?

Sure! Here's a basic example:

const knex = require('knex')({
  client: 'pg',
  connection: {
    host: '127.0.0.1',
    user: 'your_username',
    password: 'your_password',
    database: 'your_database'
  }
});

knex('users').select('*').then(rows => {
  console.log(rows);
});

What if I want to add a WHERE clause?

You can chain the where method to your query. For example:

knex('users').select('*').where('age', '>', 18).then(rows => {
  console.log(rows);
});

How do I handle errors in Knex.js?

You can use .catch() to handle errors. For example:

knex('users').select('*').then(rows => {
  console.log(rows);
}).catch(error => {
  console.error('Error:', error);
});