cheatsheets/wip/knex.md

title	category	layout
Knex	Hidden	2017/sheet

Getting started

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Create table

knex.schema.createTable('accounts', (table) => {
  table.increments('id')
  table.string('account_name')
  table.integer('user_id').unsigned().references('users.id')
})
.then(() => {
})

Select

knex('users')
  .where({ email: 'hello@example.com' })
  .then(rows => {
  })

Connect

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Libraries

| pg | PostgreSQL | | mysql | MySQL or MariaDB | | sqlite3 | Sqlite3 | | mssql | MSSQL |

Install any of these packages along with knex.

See: Node.js installation

Connect via host

var knex = require('knex')({
  client: 'mysql',
  connection: {
    host: '127.0.0.1',
    user: 'your_database_user',
    password: 'your_database_password',
    database: 'myapp_test'
  },
  pool: { min: 0, max: 7 }
})

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See: Initializing the library

Connect via URL

var pg = require('knex')({
  client: 'pg',
  connection: process.env.DATABASE_URL,
  searchPath: 'knex,public',
  pool: { min: 0, max: 7 }
})

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Connect via Sqlite

var knex = require('knex')({
  client: 'sqlite3',
  connection: { filename: './mydb.sqlite' }
})

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Select

Where

knex
  .from('books')
  .select('title', 'author', 'year')

Where

  .where('title', 'Hello')
  .where({ title: 'Hello' })
  .whereIn('id', [1, 2, 3])
  .whereNot(···)

Where conditions

  .whereNull('updated_at')
  .whereNotNull(···)

  .whereExists('updated_at')
  .whereNotExists(···)

  .whereBetween('votes', [1, 100])
  .whereNotBetween(···)

  .whereRaw('id = ?', [1])

Where grouping

  .where(function () {
    this
      .where('id', 1)
      .orWhere('id', '>', 10)
  })

Join

knex('users')

Basic join

  .join('contacts', 'users.id', '=', 'contacts.id')
  .join('contacts', {'users.id': 'contacts.id'})

Strings

  .join('accounts', 'accounts.type', '=', knex.raw('?', ['admin']))

Directions

  .leftJoin(···)
  .leftOuterJoin(···)
  .rightJoin(···)
  .rightOuterJoin(···)
  .outerJoin(···)
  .fullOuterJoin(···)
  .crossJoin(···)

Raw

  .joinRaw('natural full join table1')

Grouping

  .join('accounts', function () {
    this
      .on('accounts.id', '=', 'users.account_id')
      .orOn('accounts.owner_id', '=', 'users.id')

      .onIn('accounts.id', [1, 2, 3, 5, 8])
      .onNotIn(···)

      .onNull('accounts.email')
      .onNotNull(···)

      .onExists(function () {
        this.select(···)
      })
      .onNotExists(···)
  })

Others

knex('users')
  .distinct()

Group

  .groupBy('count')
  .groupByRaw('year WITH ROLLUP')

Order

  .orderBy('name', 'desc')
  .orderByRaw('name DESC')

Offset/limit

  .offset(10)
  .limit(20)

Having

  .having('count', '>', 100)
  .havingIn('count', [1, 100])

Union

  .union(function() {
    this.select(···)
  })
  .unionAll(···)

Etc

knex('users')
  .pluck('id')
  .then(ids => { ··· })

knex('users')
  .first()
  .then(user => { ··· })

Booleans

  .count('active')
  .count('active as is_active')

Numbers

  .min('age')
  .max('age')
  .sum('age')
  .sumDistinct('age')
  .avg('age')

Schema

Create table

knex.schema.createTable('accounts', (table) => {
  table.increments('id')
  table.string('account_name')
  table.integer('user_id').unsigned().references('users.id')
})
.then(() => {
})

Migrations

Setting up

Creates knexfile.js

./node_modules/.bin/knex init

Create a migration

knex migrate:make migration_name

Run migrations

knex migrate:latest
knex migrate:latest --env production

Rollback

knex migrate:rollback