node js knex sqlite query

Node.js Knex SQLite Query

If you're working with Node.js and SQLite, you may have heard of Knex. Knex is a SQL query builder that supports multiple database backends, including SQLite. Here's an overview of how to use Knex to execute SQL queries against a SQLite database.

Installation

First, you'll need to install Knex and SQLite:

npm install knex sqlite3

Connecting to the Database

To connect to your SQLite database using Knex, you'll need to create a new Knex instance and pass in your database configuration:

const knex = require('knex')({
    client: 'sqlite3',
    connection: {
      filename: './mydatabase.sqlite'
    }
  });

Executing Queries

Once you've connected to your database, you can execute queries using Knex's query builder. Here's an example of how to select all rows from a table:

knex.select('*').from('mytable')
    .then(rows => {
      console.log(rows);
    })
    .catch(error => {
      console.error(error);
    });

Multiple Ways to Execute Queries

Knex provides multiple ways to execute queries. Here are a few examples:

• Selecting Specific Columns: You can specify which columns to select by passing an array of column names to the "select" method.
• Filtering Rows: You can filter rows by adding a "where" clause to your query.
• Ordering Rows: You can order rows by adding an "order by" clause to your query.
• Paginating Results: You can paginate results by adding a "limit" and "offset" clause to your query.
• Joining Tables: You can join multiple tables together by adding a "join" clause to your query.

Conclusion

Using Knex to execute queries against a SQLite database in Node.js is relatively straightforward. Once you've connected to your database, you can use Knex's query builder to execute queries in a variety of ways.