# [knex.js](http://knexjs.org)
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> **A SQL query builder that is _flexible_, _portable_, and _fun_ to use!**
A batteries-included, multi-dialect (MSSQL, MySQL, PostgreSQL, SQLite3, Oracle (including Oracle Wallet Authentication)) query builder for
Node.js, featuring:
- [transactions](http://knexjs.org/#Transactions)
- [connection pooling](http://knexjs.org/#Installation-pooling)
- [streaming queries](http://knexjs.org/#Interfaces-Streams)
- both a [promise](http://knexjs.org/#Interfaces-Promises) and [callback](http://knexjs.org/#Interfaces-Callbacks) API
- a [thorough test suite](https://travis-ci.org/tgriesser/knex)
- the ability to [run in the Browser](http://knexjs.org/#Installation-browser)
Node.js versions 8+ are supported.
[Read the full documentation to get started!](http://knexjs.org)
[Or check out our Recipes wiki to search for solutions to some specific problems](https://github.com/tgriesser/knex/wiki/Recipes)
If upgrading from older version, see [Upgrading instructions](https://github.com/tgriesser/knex/blob/master/UPGRADING.md)
For support and questions, join the `#bookshelf` channel on freenode IRC
For an Object Relational Mapper, see:
- http://bookshelfjs.org
- https://github.com/Vincit/objection.js
To see the SQL that Knex will generate for a given query, see: [Knex Query Lab](http://michaelavila.com/knex-querylab/)
## Examples
We have several examples [on the website](http://knexjs.org). Here is the first one to get you started:
```js
const knex = require('knex')({
dialect: 'sqlite3',
connection: {
filename: './data.db',
},
});
// Create a table
knex.schema
.createTable('users', function(table) {
table.increments('id');
table.string('user_name');
})
// ...and another
.createTable('accounts', function(table) {
table.increments('id');
table.string('account_name');
table
.integer('user_id')
.unsigned()
.references('users.id');
})
// Then query the table...
.then(function() {
return knex('users').insert({ user_name: 'Tim' });
})
// ...and using the insert id, insert into the other table.
.then(function(rows) {
return knex('accounts').insert({ account_name: 'knex', user_id: rows[0] });
})
// Query both of the rows.
.then(function() {
return knex('users')
.join('accounts', 'users.id', 'accounts.user_id')
.select('users.user_name as user', 'accounts.account_name as account');
})
// .map over the results
.map(function(row) {
console.log(row);
})
// Finally, add a .catch handler for the promise chain
.catch(function(e) {
console.error(e);
});
```